Epoxy resin composition, fiber reinforced composite material, molded article and pressure vessel

ABSTRACT

One purpose of the present invention is to provide an epoxy resin composition which is for obtaining a fiber-reinforced composite material that combines heat resistance with tensile strength on a high level. Another purpose is to provide: a fiber-reinforced composite material obtained using this epoxy resin composition; and a molded article and a pressure vessel both containing the fiber-reinforced composite material. The present invention has the following configuration in order to achieve the above purposes. Namely, the epoxy resin composition includes the constituent element [A]: An epoxy resin including an aromatic ring and having a functionality of 2 or higher and the following constituent element [B]: An amine-based hardener, and is characterized in that a cured object obtained by curing the epoxy resin composition has a rubber-state modulus of 10 MPa or less when evaluated for dynamic viscoelasticity and the cured object has a glass transition temperature of 95° C. or higher.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. application Ser.No. 15/580,375, filed Dec. 7, 2017, which is the U.S. National Phaseapplication of PCT/JP2016/068504, filed Jun. 22, 2016, which claimspriority to Japanese Patent Application Nos. 2015-127390, filed Jun. 25,2015; JP 2015-127391, filed Jun. 25, 2015; JP 2015-127392, filed Jun.25, 2015; JP 2015-127393, filed Jun. 25, 2015; and JP 2015-253486, filedDec. 25, 2015, the disclosures of each of these applications beingincorporated herein by reference in their entireties for all purposes.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an epoxy resin composition, a fiberreinforced material containing a cured product of the epoxy resincomposition as a matrix resin, a molded article, and a pressure vessel.

BACKGROUND OF THE INVENTION

Epoxy resins are widely used in industrial fields of coating materials,adhesives, electric and electronic information materials, advancedcomposite materials and the like owing to their excellent mechanicalproperties. Epoxy resins are particularly heavily used in fiberreinforced materials made from a reinforcing fiber such as a carbonfiber, a glass fiber, and an aramid fiber, and a matrix resin.

As a method for producing the fiber reinforced material, an appropriatemethod is selected from methods such as a prepreg method, hand lay-up,filament winding, pultrusion, and Resin Transfer Molding (RTM). Of thesemethods, the filament winding, pultrusion, and RTM in which a liquidresin is used are particularly actively applied to industrialapplications such as pressure vessels, electric wires, and automobiles.

Generally, a fiber reinforced material produced by the prepreg methodhas excellent mechanical properties because the arrangement of thereinforcing fiber is precisely controlled. Meanwhile, with the recentgrowing interest in the environment and the trend toward greenhouse gasemission control, higher strength is required of fiber reinforcedmaterials made from a liquid resin similarly to those produced by theprepreg method.

Patent Document 1 discloses a resin for RIM that contains an aliphaticamine hardener and an aromatic amine hardener in combination, rapidlycures at low temperatures, and is excellent in heat resistance. PatentDocument 1 also discloses the use of 2,6-diethylaniline as the aromaticamine hardener.

Patent Document 2 discloses an epoxy resin composition that contains aspecific bifunctional epoxy resin and a specific aromatic diaminehardener, and is capable of providing a fiber reinforced materialexcellent in heat resistance, compression strength, and toughness.

Patent Document 3 discloses a low-viscosity epoxy resin composition thatcontains two kinds of different hardeners and is excellent in produceability.

Patent Document 4 discloses an epoxy resin composition that containsp-tert-butyl phenyl glycidyl ether as a reactive compound and isexcellent in heat resistance and compression properties.

Patent Document 5 discloses an epoxy resin composition that ischaracterized in having a rubbery plateau portion modulus of 10 MPa orless, and capable of providing a prepreg excellent in adhesion to ahoneycomb core and tensile strength.

Patent Document 6 discloses a resin composition that contains a resincomposed of a tri- or tetrafunctional epoxy resin and hardenersdifferent in reactivity, and is capable of improving produce ability andcompression properties. Patent Document 6 also discloses the use of4-aminodiphenylamine, which is an aromatic diamine, as a hardener.

Patent Document 7 discloses an epoxy resin composition for a tow prepregthat contains an acid anhydride as a hardener, and is excellent in heatresistance and fracture toughness.

Patent Document 8 discloses a low-viscosity epoxy resin composition thatcontains a polyfunctional epoxy resin excellent in heat resistance andan acid anhydride as a hardener, and is excellent in heat resistance andrapid-curing property.

Patent Document 9 discloses an epoxy resin composition for RTM thatcontains an alicyclic epoxy resin, and is excellent in the balancebetween strength and elongation.

Patent Document 10 discloses a resin for RTM that contains a substitutedphenyl glycidyl ether, and is capable of providing a fiber reinforcedmaterial excellent in workability and mechanical strength.

Patent Document 11 discloses a resin composition that contains amonofunctional epoxy, in particular, glycidyl phthalimide, and atrifunctional or higher functional epoxy resin, and is capable ofimproving impact resistance and mechanical characteristics at lowtemperatures.

Patent Documents 12 and 13 disclose an epoxy resin composition for FRPthat contains an epoxy having a pendant group or a monofunctional epoxyand a polyfunctional epoxy, and is excellent in heat resistance andstrength properties.

Patent Document 14 discloses an epoxy resin composition that combinesheat resistance with mechanical properties owing to incorporation of athermoplastic resin.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: Published Japanese Translation No. 2015-508125-   Patent Document 2: Japanese Patent Laid-open Publication No.    2010-150311-   Patent Document 3: Published Japanese Translation No. 2014-521824-   Patent Document 4: Japanese Patent No. 4687167-   Patent Document 5: Japanese Patent Laid-open Publication No.    2001-323046-   Patent Document 6: Published Japanese Translation No. 2008-508113-   Patent Document 7: Japanese Patent Laid-open Publication No.    2012-56980-   Patent Document 8: Japanese Patent Laid-open Publication No.    2015-3938-   Patent Document 9: Japanese Patent Laid-open Publication No.    2013-1711-   Patent Document 10: Japanese Patent Laid-open Publication No.    2005-120127-   Patent Document 11: Japanese Patent Laid-open Publication No.    2010-59225-   Patent Document 12: Japanese Patent Laid-open Publication No.    2012-67190-   Patent Document 13: International Publication No. 2011/118106-   Patent Document 14: Japanese Patent Laid-open Publication No.    63-86758

SUMMARY OF THE INVENTION

Patent Document 1 discloses a low-viscosity resin excellent incurability and heat resistance, but the resin is insufficient inmechanical properties as carbon fiber-reinforced plastic (hereinaftersometimes referred to as CFRP), and is also insufficient in tensilestrength.

The fiber reinforced material of Patent Document 2 is described asexcellent in open hole tensile strength and compression strength, but isinsufficient in tensile strength.

Patent Document 3 does not specifically mention mechanicalcharacteristics such as tensile strength of the fiber reinforcedmaterial.

Patent Document 4 is capable of providing a molded article of a fiberreinforced material excellent in compression strength, but the moldedarticle is insufficient in tensile strength.

The resin of Patent Document 5 is designed for prepregs and has a highviscosity, and cannot be applied to a process in which a liquid resin isused. Moreover, although the resin has high heat resistance, the fiberreinforced material of Patent Document 5 is insufficient in tensilestrength.

Patent Document 6 discloses a low-viscosity resin having heatresistance, but the fiber reinforced material of Patent Document 6 isinsufficient in tensile strength.

Patent Document 7 discloses a low-viscosity resin excellent in heatresistance and fracture toughness, but the resin is insufficient inmechanical properties as CFRP and is also insufficient in tensilestrength.

Patent Documents 8 and 9 also disclose a low-viscosity resin having heatresistance, but the resin is insufficient in mechanical properties asCFRP and is also insufficient in tensile strength.

Patent Document 10 discloses a low-viscosity resin having heatresistance, but the resin is insufficient in mechanical properties asCFRP and is also insufficient in tensile strength.

The resin composition disclosed in Patent Document 11 is intended forprepregs and has a high viscosity, and cannot be applied to a process inwhich a liquid resin is used. In addition, the performance of this resincomposition is improved by control of the arrangement of thermoplasticparticles. It is difficult to apply such a design unique to a laminateto a process in which a liquid resin is used, in particular, pultrusionor filament winding.

Patent Documents 12, 13, and 14 also disclose a resin excellent in heatresistance, but the fiber reinforced material of Patent Documents 12,13, and 14 is insufficient in tensile strength.

In addition, the resin of Patent Document 14 contains a thermoplasticresin for improvement in mechanical properties such as tensile strength,and it is difficult to apply the resin to a process in which a liquidresin is used.

Accordingly, an object of the present invention is to provide an epoxyresin composition intended for providing a fiber reinforced materialthat combines heat resistance with tensile strength at a high level.Another object of the present invention is to provide a fiber reinforcedmaterial made from the epoxy resin composition, and a molded article anda pressure vessel made from the fiber reinforced material.

As a result of intensive studies to solve the above-mentioned problems,the present inventors have found an epoxy resin composition having thefollowing constitution, and have completed the present invention. Thatis, the epoxy resin composition of the present invention has thefollowing constitution.

The epoxy resin composition of the present invention is an epoxy resincomposition containing the following constituent elements [A] and [B],wherein the epoxy resin composition cured into a cured product has arubbery state elastic modulus in a dynamic viscoelasticity evaluation of10 MPa or less, and the cured product has a glass transition temperatureof 95° C. or higher:

[A] a bifunctional or higher functional epoxy resin containing anaromatic ring; and

[B] an amine hardener or an acid anhydride hardener.

The fiber reinforced material of the present invention is made from acured product of the epoxy resin composition and a reinforcing fiber.

Further, the molded article and the pressure vessel of the presentinvention are made from the fiber reinforced material.

Use of the epoxy resin composition of the present invention provides afiber reinforced material excellent in heat resistance and tensilestrength. The epoxy resin composition also provides a molded article anda pressure vessel made from the fiber reinforced material.

DETAILED DESCRIPTION OF THE INVENTION

The epoxy resin composition of the present invention is an epoxy resincomposition containing the following constituent elements [A] and [B],wherein the epoxy resin composition cured into a cured product has arubbery state elastic modulus in a dynamic viscoelasticity evaluation of10 MPa or less, and the cured product has a glass transition temperatureof 95° C. or higher:

[A] a bifunctional or higher functional epoxy resin containing anaromatic ring; and

[B] an amine hardener or an acid anhydride hardener.

The epoxy resin composition of the present invention contains theabove-mentioned constituent elements [A] and [B].

The constituent element [A] is a bifunctional or higher functional epoxyresin containing an aromatic ring. The bifunctional or higher functionalepoxy resin is a compound having two or more epoxy groups in onemolecule. Examples of such an epoxy resin include bisphenol A epoxyresin, bisphenol F epoxy resin, bisphenol S epoxy resin, biphenyl epoxyresin, naphthalene epoxy resin, an epoxy resin containing adicyclopentadiene backbone, fluorene epoxy resin; novolac epoxy resinssuch as phenol novolac epoxy resin, and cresol novolac epoxy resin;biphenyl aralkyl epoxy resin and ZYLOCK epoxy resin; and glycidyl amineepoxy resins such as N,N,O-triglycidyl-m-aminophenol,N,N,O-triglycidyl-p-aminophenol,N,N,O-triglycidyl-4-amino-3-methylphenol,N,N,N′,N′-tetraglycidyl-4,4′-methylenedianiline,N,N,N′,N′-tetraglycidyl-2,2′-diethyl-4,4′-methylenedianiline,N,N,N′,N′-tetraglycidyl-m-xylylenediamine, and diglycidyl aniline. Thesemay be used singly or in combination of plural kinds.

The constituent element [B] is an amine hardener or an acid anhydridehardener. The amine hardener is a compound having one or more primary orsecondary amino groups in the molecule, and examples thereof includealiphatic polyamines and aromatic polyamines.

The acid anhydride hardener is a compound having one or more acidanhydride groups in the molecule, and examples thereof includemethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride,methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylnadic anhydride, maleic anhydride, and succinic anhydride.

The epoxy resin composition of the present invention cured into a curedproduct has a rubbery state elastic modulus in the dynamicviscoelasticity evaluation of 10 MPa or less, and the cured product hasa glass transition temperature of 95° C. or higher. When the rubberystate elastic modulus and the glass transition temperature are setwithin these ranges, the resulting fiber reinforced material exhibitsexcellent heat resistance and high tensile strength translation rate.

In the present invention, the heat resistance of the fiber reinforcedmaterial is evaluated based on the glass transition temperature of thefiber reinforced material. The tensile strength of the fiber reinforcedmaterial is evaluated based on the tensile strength translation rate.The tensile strength translation rate is an index of utilization of thestrength of the reinforcing fiber by the fiber reinforced material. Afiber reinforced material having higher tensile strength translationrate has higher strength than other fiber reinforced materials includingthe same amount of a reinforcing fiber of the same kind.

When the rubbery state elastic modulus obtained by the dynamicviscoelasticity evaluation of the epoxy resin composition of the presentinvention cured into a cured product is set to 10 MPa or less, a fiberreinforced material excellent in tensile strength translation rate, thatis, excellent in tensile strength is obtained. Herein, the rubbery stateelastic modulus is an index having a correlation with the cross-linkingdensity. In general, the lower the cross-linking density is, the lowerthe rubbery state elastic modulus is. The tensile strength translationrate is represented by (tensile strength of fiber reinforcedmaterial)/(tensile strength of reinforcing fiber strands×fiber volumecontent)×100. A larger tensile strength translation rate value meansthat the performance of the reinforcing fiber is more effectivelyutilized, and it can be said that a large effect of weight reduction isexerted.

When the glass transition temperature of the epoxy resin compositioncured into a cured product is set to 95° C. or higher, distortion of thefiber reinforced material and deterioration of mechanicalcharacteristics caused by the deformation can be suppressed, and a fiberreinforced material excellent in environmental resistance can beobtained. The conditions for curing the epoxy resin composition of thepresent invention are not particularly limited, and are appropriatelyselected according to the properties of the hardener.

Both the rubbery state elastic modulus and the glass transitiontemperature are indices related to the cross-linking density of thecured epoxy resin. When the rubbery state elastic modulus is high, thecross-linking density is high, and the glass transition temperature isalso high. On the other hand, when the rubbery state elastic modulus islow, the cross-linking density is low, and the glass transitiontemperature is also low. In the present invention, it was found that thelower the rubbery state elastic modulus is, that is, the lower thecross-linking density is, the more the fiber reinforced material isimproved in tensile strength. The present invention also overcomes theproblem of deterioration of the heat resistance caused by decrease ofthe rubbery state elastic modulus.

That is, in general, there is a trade-off relationship between a lowrubbery state elastic modulus and a high glass transition temperature.The epoxy resin composition of the present invention, however, is aliquid epoxy resin composition that overcomes this trade-offrelationship and is capable of providing a fiber reinforced materialthat combines excellent heat resistance with high tensile strength.

Preferably, the epoxy resin composition according to a first preferableaspect of the present invention contains the following constituentelements [a1] and [a2] as the constituent element [A], and contains thefollowing constituent elements [b1] and [b2] as the constituent element[B]:

[a1] a trifunctional or higher functional aromatic epoxy resin;

[a2] an optionally substituted glycidyl aniline; [b1] an aromaticdiamine having a substituent at an ortho position of each amino group ora cycloalkyldiamine having a substituent on a carbon atom adjacent to acarbon atom bonded to each amino group; and

[b2] at least one amine selected from the group consisting of4,4′-methylenebiscyclohexylamine, 1,3-bisaminomethylcyclohexane,N-cyclohexyl-1,3-propanediamine, and isophoronediamine.

The constituent element [a1] is a trifunctional or higher functionalaromatic epoxy resin. The trifunctional or higher functional epoxy resinis a compound having three or more epoxy groups in one molecule.Examples of such an epoxy resin include trifunctional or higherfunctional novolac epoxy resins such as trifunctional or higherfunctional phenol novolac epoxy resins and trifunctional or higherfunctional cresol novolac epoxy resins; and glycidyl amine epoxy resinssuch as N,N,O-triglycidyl-m-aminophenol,N,N,O-triglycidyl-p-aminophenol,N,N,O-triglycidyl-4-amino-3-methylphenol,N,N,N′,N′-tetraglycidyl-4,4′-methylenedianiline,N,N,N′,N′-tetraglycidyl-2,2′-diethyl-4,4′-methylenedianiline, andN,N,N′,N′-tetraglycidyl-m-xylylenediamine. In particular, an epoxy resinwhich is liquid at room temperature is suitably used because such anepoxy resin improves the impregnating property into a reinforcing fiber.

The constituent element [a2] is an optionally substituted glycidylaniline. Examples of the substituent include an alkyl group having 1 to4 carbon atoms, a phenyl group, and a phenoxy group. An alkyl grouphaving 1 to 4 carbon atoms is preferable because it suppresses theviscosity increase of the epoxy resin. Examples of such an epoxy resininclude diglycidyl aniline and diglycidyl toluidine.

The epoxy resin according to the first preferable aspect of the presentinvention preferably contains 20 to 40 parts by mass of the constituentelement [a1] and 20 to 60 parts by mass of the constituent element [a2]in 100 parts by mass of the total epoxy resin. When the amounts of theconstituent elements [a1] and [a2] are set within these ranges, a curedepoxy resin capable of providing a fiber reinforced material excellentin the balance between heat resistance and tensile strength translationrate can be easily obtained.

The epoxy resin composition according to the first preferable aspect ofthe present invention may further contain an epoxy resin other than theconstituent elements [a1] and [a2] as long as the effect of the presentinvention is not impaired, in particular, as long as the viscosity iswithin a tolerable range. The epoxy resin other than the constituentelements [a1] and [a2] is suitably used because such an epoxy resin canadjust the balance among mechanical properties, heat resistance, andimpact resistance, and process compatibility such as viscosity dependingon the intended use.

Examples of the epoxy resin other than the constituent elements [a1] and[a2] include reactive diluents having an epoxy group, such as bisphenolA epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin,biphenyl epoxy resin, naphthalene epoxy resin, and a monofunctionalepoxy. These may be used singly or in combination of plural kinds.

The constituent element [b1] is an aromatic diamine having a substituentat an ortho position of each amino group or a cycloalkyldiamine having asubstituent on a carbon atom adjacent to a carbon atom bonded to eachamino group.

The diamine of the constituent element [b1] has a substituent near eachof two amino groups, and has steric effects near an amino group servingas a reaction point. The substituents may be the same or different. Asthe substituent, an alkyl group having 1 to 4 carbon atoms is suitablyused.

Examples of the aromatic diamine having a substituent at an orthoposition of each amino group include 2,6-diaminotoluene,diethyltoluenediamine, 4,4′-diamino-3,3′-diethyldiphenylmethane,4,4′-diamino-3,3′-dimethyldiphenylmethane,4,4′-diamino-3,3′,5,5′-tetramethyldiphenylmethane, and4,4′-diamino-3,3′,5,5′-tetraethyldiphenylmethane.

Examples of the cycloalkyldiamine having a substituent on a carbon atomadjacent to a carbon atom bonded to each amino group include3,3′-dimethyl-4,4′-diaminodicyclohexylmethane. These amine hardeners maybe used singly or in combination.

The constituent element [b2] is at least one amine selected from thegroup consisting of 4,4′-methylenebiscyclohexylamine,1,3-bisaminomethylcyclohexane, N-cyclohexyl-1,3-propanediamine, andisophoronediamine. The amine of the constituent element [b2] is an aminecontaining a cyclohexane ring in the molecule and having certain stericconfinement near an amino group.

The epoxy resin composition according to the first preferable aspect ofthe present invention may further contain an amine other than theconstituent elements [b1] and [b2] as long as the effect of the presentinvention is not impaired. Examples of such an amine includediethylenetriamine, triethylenetetramine, hexamethylenediamine,N-aminoethylpiperazine, xylylenediamine, and an aliphatic polyaminehaving an alkylene glycol structure. Examples of the alkylene glycolstructure include polyoxyethylene, polyoxypropylene, and copolymers ofpolyoxyethylene and polyoxypropylene.

Further, the content of the constituent element [b2] is preferably inthe range of 20 to 40 parts by mass in 100 parts by mass of the totalhardener. When the content of the constituent element [b2] component isset within this range, a cured epoxy resin capable of providing a fiberreinforced material excellent in the balance between heat resistance andtensile strength translation rate can be easily obtained.

The total amount of the amines serving as the hardener is preferably 0.6to 1.2 equivalents in terms of the active hydrogen equivalent based onthe epoxy groups of all the epoxy resin components contained in theepoxy resin composition. When the total amount of the amines is setwithin this range, a cured epoxy resin capable of providing a fiberreinforced material excellent in the balance between heat resistance andmechanical properties can be easily obtained.

The reason why the epoxy resin according to the first preferable aspectof the present invention combines heat resistance with tensile strengthtranslation rate well, in other words, combines heat resistance with lowrubbery state elastic modulus well is not clear. However, it ispresumably because the steric features included in the constituentelements adjust an appropriate balance between the cross-linkage bycovalent bonds and the polymer chain confinement due to steric effects.More specifically, the following matter is conceivable: the constituentelement [a1] that increases the cross-linking density and improves heatresistance, and the constituent elements [a2] and [b1] that restrict themovement of the molecular chain by potent steric effects adjust thesteric interference between the constituent element [A] including theconstituent elements [a1] and [a2] and the constituent element [b1] withmoderate steric effects and cross-linking density, and the constituentelement [b2] that improves the balance between the cross-linkage bycovalent bonds and the polymer chain confinement due to steric effectsalso makes an effective contribution. That is, the cured epoxy resinobtained by curing the combination of the constituent elements [a1],[a2], [b1], and [b2] combines a low rubbery state elastic modulus with ahigh glass transition temperature well. Further, when the epoxy resincomposition is used as a matrix resin, a fiber reinforced materialexcellent in heat resistance and tensile strength translation rate canbe easily obtained.

Preferably, the epoxy resin composition according to a second preferableaspect of the present invention contains the following constituentelement [a1] as the constituent element [A], and contains the followingconstituent elements [b1] and [b3] as the constituent element [B]:

[a1] a trifunctional or higher functional aromatic epoxy resin;

[b1] an aromatic diamine having a substituent at an ortho position ofeach amino group or a cycloalkyldiamine having a substituent on a carbonatom adjacent to a carbon atom bonded to each amino group; and

[b3] an aromatic monoamine represented by the following general formula(I) or (II):

wherein R¹ is a substituent selected from a hydrogen atom and an alkylgroup having 1 to 4 carbon atoms, and R² is a substituent selected froman oxygen atom, a sulfonyl group, and a methylene group; or

wherein R³ is a substituent selected from a hydrogen atom and an alkylgroup having 1 to 4 carbon atoms.

The trifunctional or higher functional aromatic epoxy resin which is theconstituent element [a1] is incorporated for the purpose of improvingthe heat resistance of the cured epoxy resin composition. Examples ofsuch an epoxy resin include trifunctional or higher functional novolacepoxy resins such as trifunctional or higher functional phenol novolacepoxy resins and trifunctional or higher functional cresol novolac epoxyresins; trifunctional or higher functional biphenyl aralkyl epoxy resinand ZYLOCK epoxy resin; and glycidyl amine epoxy resins such asN,N,O-triglycidyl-m-aminophenol, N,N,O-triglycidyl-p-aminophenol,N,N,O-triglycidyl-4-amino-3-methylphenol,N,N,N′,N′-tetraglycidyl-4,4′-methylenedianiline,N,N,N′,N′-tetraglycidyl-2,2′-diethyl-4,4′-methylenedianiline,N,N,N′,N′-tetraglycidyl-m-xylylenediamine, andN,N,N′,N′-tetraglycidyl-p-xylylenediamine. In particular, an epoxy resinwhich is liquid at room temperature is suitably used because such anepoxy resin improves the impregnating property into a reinforcing fiber.

In order to make it easier to provide an epoxy resin composition thatcombines low rubbery state elastic modulus with excellent heatresistance, the content of the constituent element [a1] is preferably inthe range of 20 to 70 parts by mass in 100 parts by mass of the totalepoxy resin. When the content of the constituent element [a1] is setwithin this range, an epoxy resin composition capable of providing acured product excellent in the balance between rubbery state elasticmodulus and glass transition temperature can be easily obtained.

Further, the epoxy resin composition may contain an epoxy resin otherthan the constituent element [a1] as long as the effect of the presentinvention is not impaired. The epoxy resin other than the constituentelement [a1] is suitably used because such an epoxy resin can adjust thebalance among mechanical properties, heat resistance, and impactresistance, and process compatibility such as viscosity.

Examples of the epoxy resin other than the constituent element [a1]include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol Sepoxy resin, biphenyl epoxy resin, naphthalene epoxy resin, an epoxyresin having a fluorene backbone, diglycidyl resorcinol, glycidyl etherepoxy resin, N,N-diglycidyl aniline, and N,N-diglycidyl-o-toluidine.These epoxy resins may be used singly or in combination of plural kinds.

The diamine of the constituent element [b1] is an aromatic diaminehaving a substituent at an ortho position of each amino group or acycloalkyldiamine having a substituent on a carbon atom adjacent to acarbon atom bonded to each amino group. The diamine has a substituentnear each of two amino groups, and has steric effects near an aminogroup serving as a reaction point. The substituents may be the same ordifferent.

As the substituent, an alkyl group having 1 to 4 carbon atoms issuitably used from the viewpoint of potent steric effects. Among them, amethyl group or an ethyl group is particularly suitably used from theviewpoint that a cured product having a high glass transitiontemperature can be easily obtained.

When an aromatic diamine having a substituent at an ortho position ofeach amino group or a cycloalkyldiamine having a substituent on a carbonatom adjacent to a carbon atom bonded to each amino group is used,steric effects produced by the constituent elements [b1] and [b3]increase the polymer chain confinement, and a fiber reinforced materialmore excellent in heat resistance and tensile strength translation ratecan be easily obtained.

Examples of the aromatic diamine having a substituent at an orthoposition of each amino group include 2,6-diaminotoluene,diethyltoluenediamine, 4,4′-diamino-3,3′-diethyldiphenylmethane,4,4′-diamino-3,3′-dimethyldiphenylmethane,4,4′-diamino-3,3′,5,5′-tetramethyldiphenylmethane, and4,4′-diamino-3,3′,5,5′-tetraethyldiphenylmethane.

Examples of the cycloalkyldiamine having a substituent on a carbon atomadjacent to a carbon atom bonded to each amino group include2,2′-dimethyl-4,4′-diaminodicyclohexylmethane,3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, and3,3′-diethyl-4,4′-diaminodicyclohexylmethane.

The aromatic monoamine which is the constituent element [b3] is suitablyused because it combines heat resistance with tensile strengthtranslation rate well. The constituent element [b3] exhibits excellentheat resistance and high tensile strength translation rate when combinedwith the constituent element [b1].

The constituent element [b3] is an aromatic monoamine represented by thefollowing general formula (I) or (II), or a combination thereof. Thecombination of the constituent element [b3] with the constituent element[a1] provides a fiber reinforced material more excellent in heatresistance and tensile strength translation rate.

In the chemical formula, R¹ is a substituent selected from a hydrogenatom and an alkyl group having 1 to 4 carbon atoms, and R² is asubstituent selected from an oxygen atom, a sulfonyl group, and amethylene group.

In the chemical formula, R³ is a substituent selected from a hydrogenatom and an alkyl group having 1 to 4 carbon atoms.

Examples of the aromatic monoamine represented by the general formula(I) include 2-aminodiphenylmethane, 4-aminodiphenylmethane,2-aminodiphenylsulfone, 4-aminodiphenylsulfone, and 4-aminodiphenylether. In particular, 4-aminodiphenyl ether has phenoxyaniline havingmore potent steric effects than aniline does. Thus, when 4-aminodiphenylether is used in combination with the constituent element [b1], it ispossible to improve the heat resistance while specifically suppressingan increase in cross-linking density.

Examples of the aromatic monoamine represented by the general formula(II) include p-toluidine, 3-methylaniline, 3-ethylaniline,3-isopropylaniline, and 3-hydroxy-4-methylaniline. In particular, anaromatic monoamine which is liquid at room temperature is suitably usedbecause such an aromatic monoamine improves the impregnating propertyinto a reinforcing fiber.

In the epoxy resin composition according to the second preferable aspectof the present invention, the constituent element [b3] is preferably anaromatic monoamine represented by the general formula (I). Since thearomatic monoamine represented by the general formula (I) of theconstituent element [b3] has more potent steric effects than thearomatic monoamine represented by the general formula (II) does, thesteric effects described later are further enhanced.

The epoxy resin composition according to the second preferable aspect ofthe present invention may further contain an aromatic amine and analiphatic amine other than the constituent elements [b1] and [b3] aslong as the effect of the present invention is not impaired.

Examples of such an aliphatic amine include aliphatic polyamines havingan alkylene glycol structure. Examples of the alkylene glycol structureinclude polyoxyethylene, polyoxypropylene, and copolymers ofpolyoxyethylene and polyoxypropylene. Among them, an aliphatic polyaminehaving an amino group at the terminal is excellent in reactivity with anepoxy resin, and easily incorporated into a network with an epoxy resin.Examples of the aliphatic polyamine having an amino group at theterminal include aliphatic polyamines having a 2-aminopropyl etherstructure, a 2-aminoethyl ether structure, or a 3-aminopropyl etherstructure.

Further, the content of the constituent element [b3] is preferably inthe range of 10 to 60 parts by mass in 100 parts by mass of the totalhardener. When the content of the constituent element [b3] is set withinthis range, an epoxy resin composition capable of providing a fiberreinforced material excellent in the balance between heat resistance andtensile strength translation rate can be easily obtained.

The amount of the amine serving as the hardener is preferably 0.6 to 1.2equivalents in terms of active hydrogen groups based on the epoxy groupsof all the epoxy resin components contained in the epoxy resincomposition. When the amount of the amine is set within this range, acured resin capable of providing a fiber reinforced material excellentin the balance between heat resistance and mechanical properties can beeasily obtained.

The reason why the epoxy resin composition according to the secondpreferable aspect of the present invention combines heat resistance withtensile strength translation rate well, in other words, combines heatresistance with low rubbery state elastic modulus well is not clear.However, it is presumably because the substituent having potent stericeffects in the constituent element [b3] interferes with the curingreaction of the constituent element [b1], and the resulting curedproduct has the cross-linkage by covalent bonds and the polymer chainconfinement due to steric effects in a well-balanced manner. In thecured epoxy resin composition, the aromatic ring of the aromaticmonoamine represented by the general formula (I) or (II) of theconstituent element [b3], as steric effects, interferes with thesubstituent at an ortho position of each amino group or a substituentadjacent to a carbon atom bonded to each amino group in the constituentelement [b1], and restricts the movement of the molecular chain. As aresult, even if the cured epoxy resin composition is low in density ofcross-linkage derived from covalent bonds, the cured epoxy resincomposition exhibits high heat resistance.

In general, the constituent element [a1] is a component that increasesthe cross-linking density to improve the heat resistance. When theconstituent element [a1] is used in combination with the constituentelements [b1] and [b3], part of the epoxy resin is affected by stericeffects and remains unreacted, and serves as additional steric effects.Thus, movement of the molecular chain is restricted in a state where thecross-linking density is low. That is, the cured epoxy resin obtained bycuring the combination of the constituent elements [a1], [b1], and [b3]combines a low rubbery state elastic modulus with excellent heatresistance. Further, when the epoxy resin composition is used as amatrix resin, a fiber reinforced material excellent in heat resistanceand tensile strength translation rate can be easily obtained.

Preferably, the epoxy resin composition according to a third preferableaspect of the present invention contains the following constituentelement [a3] as the constituent element [A], and contains the followingconstituent elements [b4] and [b5] as the constituent element [B]:

[a3] a bifunctional or higher functional epoxy resin having a fluorenestructure;

[b4] an acid anhydride represented by the following general formula(III):

wherein R⁴ represents anyone of linear or branched alkyl, alkenyl, andalkynyl groups having 6 to 16 carbon atoms; and

[b5] at least one acid anhydride selected from the group consisting oftetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, andmethylhexahydrophthalic anhydride.

The constituent element [a3] is a bifunctional or higher functionalepoxy resin having a fluorene structure. Examples of such an epoxy resininclude a diglycidyl ether of bishydroxyphenylfluorene.

The acid anhydride represented by the general formula (III) which is theconstituent element [b4] is suitably used because it is excellent inheat resistance and tensile strength translation rate. The constituentelement [b4] is incorporated for the purpose of increasing the tensilestrength translation rate while suppressing the deterioration of theheat resistance. In addition, in order to combine the heat resistancewith the tensile strength translation rate, the number of carbon atomsof the substituent represented by R⁴ in the constituent element [b4]should be in the range of 6 to 16, preferably in the range of 8 to 12.Examples of such an acid anhydride include 3-dodecenylsuccinic anhydrideand octenyl succinic anhydride.

The constituent element [b5] exhibits excellent heat resistance and hightensile strength translation rate when combined with the constituentelement [b4].

The constituent element [b5] is at least one acid anhydride selectedfrom the group consisting of tetrahydrophthalic anhydride,methyltetrahydrophthalic anhydride, methyl nadic anhydride,hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

The total amount of the constituent elements [b4] and [b5] is preferablyin the range of 0.6 to 1.2 equivalents in terms of the acid anhydrideequivalent based on the epoxy groups of all the epoxy resin componentscontained in the epoxy resin composition. When the total amount is setwithin this range, a cured resin capable of providing a fiber reinforcedmaterial excellent in the balance between heat resistance and mechanicalproperties can be easily obtained.

When an acid anhydride is used as a hardener, an accelerator isgenerally used in combination. As the accelerator, an imidazoleaccelerator, a DBU salt, a tertiary amine, a Lewis acid or the like isused.

The epoxy resin composition according to the third preferable aspect ofthe present invention preferably has a ratio of parts by mass of theconstituent element [b4] to the sum of parts by mass of the constituentelements [b4] and [b5] of 0.3 to 0.6. When the content ratio of theconstituent element [b4] is set within this range, an epoxy resincomposition capable of providing a cured product excellent in thebalance between rubbery state elastic modulus and glass transitiontemperature can be easily obtained.

This effect is even greater if the constituent element [A] includes theconstituent element [a3]. In the cured epoxy resin composition, thefluorene ring of the constituent element [a3], as steric effects,interferes with R⁴ of the constituent element [b4] and the cycloalkaneor cycloalkene moiety of the constituent element [b5], and restricts themovement of the molecular chain. As a result, even if the cured epoxyresin composition is low in density of cross-linkage derived fromcovalent bonds, the cured epoxy resin composition exhibits high heatresistance. In addition, since the constituent element [a3] is solid, itincreases the viscosity of the epoxy resin composition. Thus, it isdifficult to apply the constituent element [a3] to the filament windingor pultrusion which normally requires a low-viscosity resin. However, inthe present invention, an epoxy resin composition having sufficientlylow viscosity can be obtained even if a solid component such as theconstituent element [a3] is incorporated, since the constituent elements[b4] and [b5] used as the hardener have a very low viscosity.

The epoxy resin composition according to the third preferable aspect ofthe present invention may further contain an epoxy resin other than theconstituent element [a3] as long as the effect of the present inventionis not impaired. The epoxy resin other than the constituent element [a3]is suitably used because such an epoxy resin can adjust the balanceamong mechanical properties, heat resistance, and impact resistance, andprocess compatibility such as viscosity depending on the intended use.

Examples of the epoxy resin other than the constituent element [a3]include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol Sepoxy resin, biphenyl epoxy resin, naphthalene epoxy resin, an epoxyresin containing a dicyclopentadiene backbone; novolac epoxy resins suchas phenol novolac epoxy resin, and cresol novolac epoxy resin; biphenylaralkyl epoxy resin and ZYLOCK epoxy resin; glycidyl amine epoxy resinssuch as N,N,O-triglycidyl-m-aminophenol,N,N,O-triglycidyl-p-aminophenol,N,N,O-triglycidyl-4-amino-3-methylphenol,N,N,N′,N′-tetraglycidyl-4,4′-methylenedianiline,N,N,N′,N′-tetraglycidyl-2,2′-diethyl-4,4′-methylenedianiline, andN,N,N′,N′-tetraglycidyl-m-xylylenediamine; alicyclic epoxy resins; andaliphatic epoxy resins.

The reason why the epoxy resin composition according to the thirdpreferable aspect of the present invention combines heat resistance withtensile strength translation rate well, in other words, combines heatresistance with low rubbery state elastic modulus well is not clear.However, it is presumably because the substituent moiety of theconstituent element [b4], that is, the moiety represented by R⁴ in theformula (III) lowers the rubbery state elastic modulus due to itsflexibility, and R⁴ of the constituent element [b4] interferes with thecycloalkane or cycloalkene moiety of the constituent element [b5], andrestricts the movement of the molecular chain. That is, the cured epoxyresin obtained by curing the combination of the constituent elements[b4] and [b5] combines a low rubbery state elastic modulus withexcellent heat resistance. Further, when the epoxy resin composition isused as a matrix resin, a fiber reinforced material excellent in heatresistance and tensile strength translation rate can be easily obtained.

Preferably, the epoxy resin composition according to a fourth preferableaspect of the present invention contains at least one of the followingconstituent elements [a2] and [a4] as the constituent element [A], andfurther contains the following constituent element [C]:

[a2] an optionally substituted diglycidyl aniline;

[a4] tetraglycidyl diaminodiphenylmethane; and

[C] a monofunctional epoxy resin which is a phenyl glycidyl ethersubstituted with a tert-butyl group, a sec-butyl group, an isopropylgroup, or a phenyl group.

A monofunctional epoxy resin which is a phenyl glycidyl ethersubstituted with a tert-butyl group, a sec-butyl group, an isopropylgroup, or a phenyl group, which is the constituent element [C], issuitably used because such a monofunctional epoxy resin is excellent inheat resistance and tensile strength translation rate. The constituentelement [C] is incorporated for the purpose of increasing the tensilestrength translation rate while suppressing the deterioration of theheat resistance. Examples of such an epoxy resin include p-tert-butylphenyl glycidyl ether, p-isopropyl phenyl glycidyl ether, p-sec-butylphenyl glycidyl ether, and o-phenylphenol glycidyl ether.

The epoxy resin composition according to the fourth preferable aspect ofthe present invention preferably contains 20 to 50 parts by mass of theconstituent element [C] in 100 parts by mass of the total epoxy resin.When the content of the constituent element [C] is set within thisrange, a cured epoxy resin capable of providing a fiber reinforcedmaterial excellent in the balance between heat resistance and tensilestrength translation rate can be easily obtained.

The constituent element [a2] or [a4] exhibits more excellent heatresistance and higher tensile strength translation rate in the obtainedfiber reinforced material when combined with the constituent element[C].

The constituent element [a2] is an optionally substituted diglycidylaniline. Examples of the epoxy resin of the constituent element [a2]include diglycidyl aniline and diglycidyl toluidine.

The constituent element [a4] is tetraglycidyl diaminodiphenylmethane.

The epoxy resin composition according to the fourth preferable aspect ofthe present invention preferably contains the constituent elements [a2]and [a4] as the constituent element [A]. This is because the epoxy resincomposition is excellent in workability as a liquid resin, and a fiberreinforced material more excellent in the balance between heatresistance and tensile strength translation rate can be easily obtained.

The epoxy resin composition according to the fourth preferable aspect ofthe present invention may further contain an epoxy resin other than theconstituent elements [a2], [a4], and [C] as long as the effect of thepresent invention is not impaired, in particular, as long as theviscosity is within a tolerable range. The epoxy resin other than theconstituent elements [a2], [a4], and [C] is suitably used because suchan epoxy resin can adjust the balance among mechanical properties, heatresistance, and impact resistance, and process compatibility such asviscosity depending on the intended use.

Examples of the epoxy resin other than the constituent elements [a2],[a4], and [C] include bisphenol A epoxy resin, bisphenol F epoxy resin,bisphenol S epoxy resin, biphenyl epoxy resin, naphthalene epoxy resin,aminophenol epoxy resin, phenol novolac epoxy resin, an epoxy resincontaining a dicyclopentadiene backbone, a phenyl glycidyl ether epoxyresin other than the constituent element [C], and a reactive diluenthaving an epoxy group. These may be used singly or in combination ofplural kinds.

The constituent element [B] is an amine hardener or an acid anhydridehardener. Examples of an aliphatic amine hardener includeisophoronediamine, diethylenetriamine, triethylenetetramine,hexamethylenediamine, N-aminoethylpiperazine, xylylenediamine,4,4′-methylenebiscyclohexylamine,3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, cyclohexanediamine,1,3-bisaminomethylcyclohexane, and an aliphatic polyamine having analkylene glycol structure. Examples of the alkylene glycol structureinclude polyoxyethylene, polyoxypropylene, and copolymers ofpolyoxyethylene and polyoxypropylene. Among them, an aliphatic polyaminehaving an amino group at the terminal is suitably used because such analiphatic polyamine is excellent in reactivity with an epoxy resin,easily incorporated into a network with an epoxy resin, and improves thetensile strength translation rate of the fiber reinforced material.Examples of the aliphatic polyamine having an amino group at theterminal include aliphatic polyamines having a 2-aminopropyl etherstructure, a 2-aminoethyl ether structure, or a 3-aminopropyl etherstructure.

Examples of an aromatic amine hardener include metaphenylenediamine,diaminodiphenylmethane, diethyltoluenediamine,4,4′-diamino-3,3′-diethyldiphenylmethane,4,4′-diamino-3,3′-dimethyldiphenylmethane,4,4′-diamino-3,3′,5,5′-tetramethyldiphenylmethane, and4,4′-diamino-3,3′,5,5′-tetraethyldiphenylmethane.

In the epoxy resin composition according to the fourth preferable aspectof the present invention, the constituent element [B] is preferably anacid anhydride hardener. The acid anhydride hardener is preferablebecause it combines low viscosity of the epoxy resin composition withheat resistance of the cured resin in a well-balanced manner.

Examples of the acid anhydride hardener include methyltetrahydrophthalicanhydride, hexahydrophthalic anhydride, methylhexahydrophthalicanhydride, tetrahydrophthalic anhydride, methyl nadic anhydride, maleicanhydride, and succinic anhydride.

The epoxy resin composition according to the fourth preferable aspect ofthe present invention preferably contains a compound having a norbornenebackbone or a norbornane backbone as the constituent element [B]. Anacid anhydride having a norbornene backbone or a norbornane backbone issuitably used because steric effects produced by the backbone increasethe polymer chain confinement, and a fiber reinforced material moreexcellent in heat resistance and tensile strength translation rate canbe easily obtained. Specific examples of the acid anhydride having anorbornene backbone or a norbornane backbone include methylendomethylene tetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methyl bicycloheptane dicarboxylicanhydride, and bicycloheptane dicarboxylic anhydride.

When an acid anhydride is used as a hardener, an accelerator isgenerally used in combination. As the accelerator, an imidazoleaccelerator, a DBU salt, a tertiary amine, a Lewis acid or the like isused.

In the epoxy resin composition according to the fourth preferable aspectof the present invention, the constituent element [B] is preferably anamine hardener, and the epoxy resin composition preferably contains thefollowing constituent element [b1] as the constituent element [B]:

[b1] an aromatic diamine having a substituent at an ortho position of anamino group or a cycloalkyldiamine having a substituent on a carbon atomadjacent to a carbon atom having an amino group.

An aromatic diamine having a substituent at an ortho position of anamino group or a cycloalkyldiamine having a substituent on a carbon atomadjacent to a carbon atom having an amino group is suitably used becausethe constituent element [b1] in combination with the constituent element[a2] or [a4] and the constituent element [C] increases the polymer chainconfinement due to steric effects, and a fiber reinforced material moreexcellent in heat resistance and tensile strength translation rate canbe easily obtained. Specific examples of the hardener includediethyltoluenediamine, 4,4′-diamino-3,3′-diethyldiphenylmethane,4,4′-diamino-3,3′-dimethyldiphenylmethane,4,4′-diamino-3,3′,5,5′-tetramethyldiphenylmethane,4,4′-diamino-3,3′,5,5′-tetraethyldiphenylmethane, and2,2′-dimethyl-4,4′-methylenebiscyclohexylamine. Among them,3,3′-dimethyl-4,4′-diaminodicyclohexylmethane and diethyltoluenediamineare preferable.

These amine hardeners may be used singly or in combination.

The epoxy resin composition according to the fourth preferable aspect ofthe present invention preferably further contains an aliphatic polyaminehaving an alkylene glycol structure as the constituent element [B]. Thecombination of an aromatic diamine having a substituent at an orthoposition of an amino group or a cycloalkyldiamine having a substituenton a carbon atom adjacent to a carbon atom having an amino group with analiphatic polyamine having an alkylene glycol structure makes it easierto improve the balance between the viscosity of the epoxy resincomposition and the glass transition temperature of the cured product,and the rubbery state elastic modulus.

The epoxy resin composition according to the fourth preferable aspect ofthe present invention preferably further contains isophoronediamine asthe constituent element [B]. When the epoxy resin composition containsisophoronediamine in addition to the cycloalkyldiamine having asubstituent on a carbon atom adjacent to a carbon atom having an aminogroup, a fiber reinforced material excellent in tensile strengthtranslation rate can be easily obtained, and the process stability isimproved. This is because the addition of isophoronediamine suppressesthe phenomenon of salt formation by the amine in the resin bath withcarbon dioxide in the air (Amine Blush), and improves the processstability.

The total amount of the constituent element [B] is preferably 0.6 to 1.2equivalents in terms of the active hydrogen equivalent or the acidanhydride equivalent based on the epoxy groups of all the epoxy resincomponents contained in the epoxy resin composition. When the totalamount of the constituent element [B] is set within this range, a curedepoxy resin capable of providing a fiber reinforced material excellentin the balance between heat resistance and mechanical properties can beeasily obtained.

The reason why the epoxy resin composition according to the fourthaspect of the present invention combines heat resistance with tensilestrength translation rate well, in other words, combines heat resistancewith low rubbery state elastic modulus well is not clear. However, it ispresumably because the substituent having potent steric effects in theconstituent element [C] interferes with the curing reaction of theconstituent element [a2] or [a4], and the cured product has thecross-linkage by covalent bonds and the polymer chain confinement due tosteric effects in a well-balanced manner. In the cured epoxy resincomposition, the aromatic ring of the constituent element [a2], assteric effects, interferes with the tert-butyl group, the isopropylgroup, or the like of the constituent element [C], and restricts themovement of the molecular chain. As a result, even if the cured epoxyresin composition is low in density of cross-linkage derived fromcovalent bonds, the cured epoxy resin composition exhibits high heatresistance. In general, the constituent element [a4] is a component thatincreases the cross-linking density to improve the heat resistance. Whenthe constituent element [a4] is used in combination with the constituentelement [C], part of the epoxy resin is affected by steric effects andremains unreacted, and serves as additional steric effects. Thus,movement of the molecular chain is restricted in a state where thecross-linking density is low as in the case of the constituent element[a2]. That is, the cured epoxy resin obtained by curing the combinationof the constituent element [A] including the constituent element [a2] or[a4], the constituent element [B], and the constituent element [C]combines a low rubbery state elastic modulus with a high glasstransition temperature. Further, when the epoxy resin composition isused as a matrix resin, a fiber reinforced material excellent in heatresistance and tensile strength translation rate can be easily obtained.

The epoxy resin composition of the present invention is suitably used ina fiber reinforced material produced by a liquid process such asfilament winding or pultrusion. The epoxy resin composition ispreferably in a liquid form in order to improve the impregnatingproperty into the reinforcing fiber bundle. More specifically, the epoxyresin composition according to the second preferable aspect of thepresent invention preferably has a viscosity at 25° C. of 3000 mPa·s orless, more preferably 2000 mPa·s or less. On the other hand, the epoxyresin composition according to the first, third, or fourth preferableaspect of the present invention preferably has a viscosity at 25° C. of2000 mPa·s or less. When the viscosity is within this range, thereinforcing fiber bundle can be impregnated with the epoxy resincomposition without requiring a special heating mechanism in the resinbath or dilution with an organic solvent or the like.

The epoxy resin composition of the present invention can contain athermoplastic resin as long as the effect of the present invention isnot impaired. The thermoplastic resin may be a thermoplastic resinsoluble in an epoxy resin, organic particles such as rubber particlesand thermoplastic resin particles, or the like.

Examples of the thermoplastic resin soluble in an epoxy resin includepolyvinyl acetal resins such as polyvinyl formal and polyvinyl butyral,polyvinyl alcohol, phenoxy resin, polyamide, polyimide, polyvinylpyrrolidone, and polysulfone.

Examples of the rubber particles include cross-linked rubber particles,and core shell rubber particles obtained by graft-polymerizing aheterogeneous polymer onto the surface of cross-linked rubber particles.

In preparing the epoxy resin composition of the present invention, forexample, the components may be kneaded using a machine such as aplanetary mixer or a mechanical stirrer, or the components may be mixedby hand using a beaker and a spatula.

The fiber reinforced material of the present invention is made from acured product of the epoxy resin composition of the present inventionand a reinforcing fiber. The fiber reinforced material of the presentinvention is preferable because it can combine heat resistance withtensile strength translation rate at a high level.

The fiber reinforced material containing a cured product of the epoxyresin composition of the present invention as a matrix resin can beobtained by integrating the epoxy resin composition of the presentinvention prepared by the above-mentioned method with a reinforcingfiber, and then curing the resulting product.

The reinforcing fiber used in the present invention is not particularlylimited, and a glass fiber, a carbon fiber, an aramid fiber, a boronfiber, an alumina fiber, a silicon carbide fiber and the like can beused. Two or more of these fibers may be used as a mixture. Of these, acarbon fiber is preferably used because it can provide a light and stifffiber reinforced material.

The epoxy resin composition of the present invention can be suitablyused in the filament winding and pultrusion. The filament winding is amolding method of winding a reinforcing fiber on a mandrel or a linerwith a resin being adhered to the reinforcing fiber, and curing theresin to give a molded article. The pultrusion is a molding method ofadhering a resin to a roving of a reinforcing fiber, and continuouslycuring the resin while passing the roving through a mold to give amolded article. In either method, the prepared epoxy resin compositionof the present invention can be put in a resin bath and used.

The fiber reinforced material made from the epoxy resin composition ofthe present invention is preferably used for pressure vessels, propellershafts, drive shafts, electric cable core materials, structures ofmoving bodies such as automobiles, ships, and railway vehicles, andcable applications. The fiber reinforced material is particularlysuitably used for the production of a pressure vessel by filamentwinding.

The molded article of the present invention is made from the fiberreinforced material of the present invention. The molded article of thepresent invention is formed by a general molding method such as handlay-up, filament winding, pultrusion, or Resin Transfer Molding. Themolded article is particularly suitably formed by the filament windingor pultrusion.

The pressure vessel of the present invention is made from the fiberreinforced material of the present invention. The pressure vessel of thepresent invention is preferably produced by filament winding. Thefilament winding is a method of winding a reinforcing fiber on a linerwith a thermosetting resin composition being adhered to the reinforcingfiber, and curing the resin composition to give a molded articleincluding a liner, and a fiber reinforced material layer that covers theliner and is made of the fiber reinforced material including thehardener for the thermosetting resin composition and the reinforcingfiber. For producing the pressure vessel, a metal liner or a liner madeof a resin such as polyethylene or polyamide is used, and a desiredmaterial can be appropriately selected. In addition, the liner shape canalso be appropriately selected according to the desired shape.

EXAMPLES

Hereinafter, the present invention will be described more specificallywith reference to examples, but the present invention is not limited tothe description of these examples.

The constituent elements used in the examples are as follows.

<Materials Used>

Constituent Element [A]

([a1]: trifunctional or higher functional aromatic epoxy resin)

[a1]-1 “Araldite (registered trademark)” MY0500(triglycidyl-p-aminophenol, manufactured by Huntsman Japan KK)

[a1]-2 “Araldite (registered trademark)” MY0510(triglycidyl-p-aminophenol, manufactured by Huntsman Japan KK)

[a1]-3 “Araldite (registered trademark)” PY307-1 (phenol novolac epoxyresin, manufactured by Huntsman Japan KK)

[a1]-4 “jER (registered trademark)” 630 (p-aminophenol epoxy resin,manufactured by Mitsubishi Chemical Corporation)

[a1]-5 “TETRAD (registered trademark)”-X(N,N,N′,N′-tetraglycidyl-m-xylenediamine, manufactured by MITSUBISHI GASCHEMICAL COMPANY, INC.)

([a2]: optionally substituted glycidyl aniline)

[a2]-1 GOT (N,N′-diglycidyl orthotoluidine, manufactured by NipponKayaku Co., Ltd.)

[a2]-2 GAN (N,N′-diglycidyl aniline, manufactured by Nippon Kayaku Co.,Ltd.)

([a3]: bifunctional or higher functional epoxy resin having fluorenestructure)

[a3]-1 “OGSOL (registered trademark)” PG-100 (fluorene epoxy resin,manufactured by Osaka Gas Chemicals Co., Ltd.)

[a3]-2 “OGSOL (registered trademark)” EG-200 (fluorene epoxy resin,manufactured by Osaka Gas Chemicals Co., Ltd.)

([a4]: tetraglycidyl diphenyldiaminomethane)→[a4] is incorporated into[a1].

[a4]-1 “SUMI-EPDXY (registered trademark)” ELM434 (tetraglycidyldiaminodiphenylmethane, manufactured by Sumitomo Chemical Co., Ltd.)

[a4]-2 “Araldite (registered trademark)” MY721(N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane, manufactured byHuntsman Japan KK)

(Other Constituent Elements [A])

[A]-1 “jER (registered trademark)” 825 (liquid bisphenol A epoxy resin,manufactured by Mitsubishi Chemical Corporation)

[A]-2 “jER (registered trademark)” 828 (liquid bisphenol A epoxy resin,manufactured by Mitsubishi Chemical Corporation)

[A]-3 “jER (registered trademark)” 806 (liquid bisphenol F epoxy resin,manufactured by Mitsubishi Chemical Corporation)

[A]-4 “jER (registered trademark)” 830 (liquid bisphenol F epoxy resin,manufactured by Mitsubishi Chemical Corporation)

[A]-5 “jER (registered trademark)” YDF2001 (solid bisphenol F epoxyresin, manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD.)

[A]-6 “jER (registered trademark)” YX4000 (biphenyl epoxy resin,manufactured by Mitsubishi Chemical Corporation)

[A]-7 “Epikote (registered trademark)” YX4000H (biphenyl epoxy resin,manufactured by Mitsubishi Chemical Corporation)

[A]-8 “HyPox (registered trademark)” RA95 (elastomer-modified bisphenolA epoxy resin, manufactured by CVC Thermoset Specialties)

Constituent Element [B]

([b1]: sterically hindered diamine)

[b1]-1 “Aradur (registered trademark)” 5200 (diethyltoluenediamine,manufactured by Huntsman Japan KK)

[b1]-2 “Etacure (registered trademark)” 100 (diethyltoluenediamine,manufactured by Albemarle)

[b1]-3 “jER Cure (registered trademark)” W (diethyltoluenediamine,manufactured by Mitsubishi Chemical Corporation)

[b1]-4 “KAYABOND (registered trademark)” C-300S(4,4′-diamino-3,3′,5,5′-tetraethyldiphenylmethane, manufactured byNippon Kayaku Co., Ltd.)

[b1]-5 2,6-diaminotoluene (manufactured by Tokyo Chemical Industry Co.,Ltd.)

[b1]-6 “Baxxodur (registered trademark)” EC331(3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, manufactured by BASFJapan Ltd.)

([b2]: alicyclic amine)

[b2]-1 “Baxxodur (registered trademark)” EC201 (isophoronediamine,manufactured by BASF Japan Ltd.)

[b2]-2 4,4′-methylenebiscyclohexylamine (manufactured by Tokyo ChemicalIndustry Co., Ltd.)

[b2]-3 1,3-bisaminomethylcyclohexane (manufactured by MITSUBISHI GASCHEMICAL COMPANY, INC.)

[b2]-4 N-cyclohexyl-1,3-propanediamine (manufactured by Tokyo ChemicalIndustry Co., Ltd.)

([b3]: aromatic monoamine)

(Aromatic Monoamine Represented by General Formula (I))

[b3]-1 4-aminodiphenyl ether (active hydrogen equivalent: 93)

[b3]-2 4-aminodiphenylmethane (active hydrogen equivalent: 92)

[b3]-3 2-aminodiphenylsulfone (active hydrogen equivalent: 117)

(Aromatic Monoamine Represented by General Formula (II))

[b3]-4 p-toluidine (active hydrogen equivalent: 54)

[b3]-5 3-methylaniline (active hydrogen equivalent: 54)

[b3]-6 3-ethylaniline (active hydrogen equivalent: 61)

[b3]-7 3-isopropylaniline (active hydrogen equivalent: 66)

([b4]: acid anhydride having flexible group)

[b4]-1 “RIKACID (registered trademark)” DDSA (3-dodecenylsuccinicanhydride, manufactured by New Japan Chemical Co., Ltd.)

Constituent Element [b5]: General Acid Anhydride

[b5]-1 HN2200 (methyltetrahydrophthalic anhydride, manufactured byHitachi Chemical Co., Ltd.)

[b5]-2 “KAYAHARD (registered trademark)” MCD (methyl nadic anhydride,manufactured by Nippon Kayaku Co., Ltd.)

(Other Constituent Elements [B])

[B]-1 3,3′-DAS (3,3′-diaminodiphenylsulfone, manufactured by Mitsui FineChemicals, Inc.)

[B]-2 “SEIKACURE (registered trademark)” S (4,4′-diaminodiphenylsulfone,manufactured by SEIKA CORPORATION)

[B]-3 4-aminodiphenylamine

[B]-4 3,3′-diaminodiphenylsulfone (manufactured by Wakayama Seika KogyoCo., Ltd.)

[B]-5 “JEFFAMINE (registered trademark)” D230 (polypropylene glycoldiamine, manufactured by Huntsman Japan KK)

[B]-6 “JEFFAMINE (registered trademark)” D400 (polypropylene glycoldiamine, manufactured by Huntsman Japan KK)

Constituent Element [C]

[C]-1 “Denacol (registered trademark)” EX-146 (p-tert-butyl phenylglycidyl ether, manufactured by Nagase ChemteX Corporation)

[C]-2 “Denacol (registered trademark)” EX-142 (o-phenylphenol glycidylether, manufactured by Nagase ChemteX Corporation) Epoxy resin otherthan constituent elements [A] and [C]

[A′]-1 “CELLOXIDE (registered trademark)” 2021P (alicyclic epoxy resin,manufactured by Daicel Corporation)

[A′]-2 “Epotohto (registered trademark)” YH-300 (aliphatic polyglycidylether, manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD.)

[A′]-3 “Denacol (registered trademark)” EX-141 (phenyl glycidyl ether,manufactured by Nagase ChemteX Corporation)

Accelerator [E]

[E]-1DY070 (imidazole, manufactured by Huntsman Japan KK)

[E]-2 “Curezol (registered trademark)” 1B2MZ (imidazole, manufactured byShikoku Chemicals Corporation)

[E]-3 “KAOLIZER (registered trademark)” No. 20 (N,N-dimethylbenzylamine,manufactured by Kao Corporation)

[E]-4 “U-CAT (registered trademark)” SA102 (DBU-octylate, San-Apro Ltd.)

[E]-5 “Curezol (registered trademark)” 2E4MZ (2-ethyl-4-methylimidazole,Shikoku Chemicals Corporation)

Other Components [F]

[F]-1 “Kane Ace (registered trademark)” MX-416 (core shell rubber 25% bymass/“Araldite (registered trademark)” MY721 (constituent element [A])75% by mass, manufactured by Kaneka Corporation)

[F]-2 DIC-TBC (4-t-butylcatechol, manufactured by DIC Corporation)

Reinforcing Fiber

“Torayca (registered trademark)” T700SC-12K-50C (tensile strength: 4.9GPa, manufactured by Toray Industries, Inc.)

<Method for Preparing Epoxy Resin Composition>

As the main ingredient of the epoxy resin composition, the epoxy resinof the constituent element [A] and, if necessary, the constituentelement [C] and other epoxy resins were charged into a beaker, and thecontents were heated to 80° C. and kneaded with heating for 30 minutes.Then, as a hardener, the constituent element [B] and, if necessary,other hardeners and accelerators were charged into another beaker. Thesolid hardener was previously kneaded at a temperature of 25 to 120° C.for 30 to 60 minutes so as to be dissolved in the liquid hardener.

Then, the temperature was lowered to 30° C. or lower with the contentsbeing continuously kneaded, and the main ingredient and the hardenerwere mixed and stirred for 10 minutes to give an epoxy resincomposition.

The content ratios of the components in each of the examples andcomparative examples are shown in Tables 1 to 13.

<Viscosity Measurement of Epoxy Resin Composition>

The viscosity of the epoxy resin composition prepared according to<Method for preparing epoxy resin composition> was measured using anE-type viscometer (manufactured by Toki Sangyo Co., Ltd., TVE-30H)equipped with a standard cone rotor (1° 34′×R24) at a rotation speed of10 revolutions/min according to “Method for measuring viscosity bycone-plate type rotational viscometer” in JIS Z 8803 (2011). After beingprepared, the epoxy resin composition was charged into an apparatus setat 25° C., and the viscosity after 1 minute was measured.

<Method for Producing Fiber Reinforced Material>

The epoxy resin composition prepared according to <Method for preparingepoxy resin composition> was impregnated into a sheet-shaped carbonfiber “Torayca (registered trademark)” T700S-12K-50C (manufactured byToray Industries, Inc., areal weight: 150 g/m²) arranged in onedirection at room temperature to give an epoxy resin-impregnated carbonfiber sheet. Then, 8 sheets were stacked so that the fibers would bearranged in the same direction, and the resulting laminate wassandwiched between molds set to a thickness of 1 mm with a metal spacer.The molds were subjected to thermal curing for 2 hours using a pressmachine. Then, the molds were taken out of the press machine, andfurther thermally cured in an oven for 4 hours to give a fiberreinforced material. As for the curing conditions, the following A or Bwas applied depending on the hardener used.

Curing conditions A: Curing at 100° C. for 2 hours, and then curing at150° C. for 4 hours

Curing conditions B: Curing at 80° C. for 2 hours, and then curing at110° C. for 4 hours

<Method for Evaluating Properties of Cured Resin>

The epoxy resin composition was defoamed in a vacuum, and then cured ina mold set to a thickness of 2 mm with a 2-mm thick “TEFLON (registeredtrademark)” spacer to give a plate-shaped cured resin having a thicknessof 2 mm. As for the curing conditions, the following A or B was applieddepending on the hardener used.

Curing conditions A: Curing at 100° C. for 2 hours, and then curing at150° C. for 4 hours

Curing conditions B: Curing at 80° C. for 2 hours, and then curing at110° C. for 4 hours

A test piece having a width of 12.7 mm and a length of 45 mm was cutfrom the cured resin. DMA measurement was carried out in the temperaturerange of 30 to 250° C. under conditions of a torsional vibrationfrequency of 1.0 Hz and a temperature ramp rate of 5.0° C./min using aviscoelasticity measuring device (ARES, manufactured by TA InstrumentsInc.), and the glass transition temperature and the rubbery stateelastic modulus were read. The glass transition temperature is thetemperature at the intersection of the tangent in the glass state andthe tangent in the transition state in the storage elastic modulus G′curve. The rubbery state elastic modulus is a storage elastic modulus ina region in which the storage elastic modulus is flat in a temperatureregion above the glass transition temperature. Herein, the storageelastic modulus at a temperature 40° C. above the glass transitiontemperature is employed.

<Tensile Strength Measurement of Fiber Reinforced Material>

From the fiber reinforced material produced according to <Method forproducing fiber reinforced material>, a test piece having a width of12.7 mm and a length of 229 mm was cut, and a glass fiber-reinforcedplastic tab of 1.2 mm, 50 mm in length was bonded to both ends of thetest piece. The tensile strength of the test piece was measured at acrosshead speed of 1.27 mm/min using an Instron universal testingmachine (manufactured by Instron) according to ASTM D 3039. The averagevalue of measured values of samples (number of samples=6) was taken asthe tensile strength.

The tensile strength translation rate was calculated according to(tensile strength of fiber reinforced material)/(tensile strength ofreinforcing fiber strands×fiber volume content)×100.

The fiber volume content was measured according to ASTM D 3171, and themeasured value was used.

<Glass Transition Temperature Measurement of Fiber Reinforced Material>

A small piece (5 to 10 mg) was collected from the fiber reinforcedmaterial produced according to <Method for producing fiber reinforcedmaterial>, and the intermediate point glass transition temperature (Tmg)was measured according to JIS K 7121 (1987). The measurement was carriedout in a Modulated mode at a temperature ramp rate of 5° C./min under anitrogen gas atmosphere using a differential scanning calorimeter DSCQ2000 (manufactured by TA Instruments Inc.).

Example 1

Using 25 parts by mass of “SUMI-EPDXY (registered trademark)” ELM434, 30parts by mass of GAN, and 45 parts by mass of “jER (registeredtrademark)” 828 as the constituent element [A], and 19 parts by mass of“Aradur (registered trademark)” 5200 and 10 parts by mass of “Baxxodur(registered trademark)” EC201 as the constituent element [B], an epoxyresin composition was prepared according to <Method for preparing epoxyresin composition>.

The epoxy resin composition was cured by the above-mentioned method toprepare a cured product, and the dynamic viscoelasticity was evaluated.As a result, the glass transition temperature was 131° C. and therubbery state elastic modulus was 8.2 MPa, and the epoxy resincomposition was satisfactory in heat resistance and rubbery stateelastic modulus.

A fiber reinforced material was produced from the obtained epoxy resincomposition according to <Method for producing fiber reinforcedmaterial> to give a fiber reinforced material having a fiber volumecontent of 65%. The tensile strength of the obtained fiber reinforcedmaterial was measured by the above-mentioned method, and the tensilestrength translation rate was calculated. As a result, the tensilestrength translation rate was 78%. In addition, the glass transitiontemperature of the obtained fiber reinforced material was 132° C.

Examples 2 to 61

An epoxy resin composition, a cured epoxy resin, and a fiber reinforcedmaterial were produced by the same method as in Example 1 (except thatthe curing conditions were the curing conditions A or B shown in thetables) except that the resin composition was changed as shown in Tables1 to 10. The evaluation results are shown in Tables 1 to 10. All of theobtained cured epoxy resins showed satisfactory heat resistance andrubbery state elastic modulus. The tensile strength translation rate andheat resistance of the obtained fiber reinforced material were alsosatisfactory.

Comparative Example 1

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 1 except that the resin composition was changed asshown in Table 11. The evaluation results are shown in Table 11. Theglass transition temperature was 115° C., and the rubbery state elasticmodulus was as high as 11.0 MPa. As a result, the tensile strengthtranslation rate of the fiber reinforced material was 72%, and wasinsufficient.

Comparative Example 2

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 1 except that the resin composition was changed asshown in Table 11. The evaluation results are shown in Table 11. Theglass transition temperature was 146° C. and satisfactory, but therubbery state elastic modulus was as high as 15.2 MPa. As a result, thetensile strength translation rate of the fiber reinforced material was68%, and was insufficient.

Comparative Example 3

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 1 except that the resin composition was changed asshown in Table 11. The evaluation results are shown in Table 11. Theglass transition temperature was 133° C. and satisfactory, but therubbery state elastic modulus was as high as 14.1 MPa. As a result, thetensile strength translation rate of the fiber reinforced material was68%, and was insufficient.

Comparative Example 4

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 1 except that the resin composition was changed asshown in Table 11. The evaluation results are shown in Table 11. Theglass transition temperature was 131° C. and satisfactory, but therubbery state elastic modulus was as high as 12.9 MPa. As a result, thetensile strength translation rate of the fiber reinforced material was71%, and was insufficient.

Comparative Example 5

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 13 except that the resin composition was changed asshown in Table 12. The evaluation results are shown in Table 12. Therubbery state elastic modulus was 9.5 MPa and was satisfactory, but theglass transition temperature was 92° C. As a result, the fiberreinforced material had a glass transition temperature of 94° C., andwas insufficient in heat resistance.

Comparative Example 6

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 13 except that the resin composition was changed asshown in Table 12. The evaluation results are shown in Table 12. Therubbery state elastic modulus was 7.8 MPa or less and was satisfactory,but the glass transition temperature was 90° C. As a result, the fiberreinforced material had a glass transition temperature of 93° C., andwas insufficient in heat resistance.

Comparative Example 7

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 13 except that the resin composition was changed asshown in Table 12. The evaluation results are shown in Table 12. Theglass transition temperature was 157° C. and the epoxy resin compositionwas satisfactory in heat resistance, but the rubbery state elasticmodulus was as high as 13.0 MPa. As a result, the tensile strengthtranslation rate of the fiber reinforced material was 71%, and wasinsufficient.

Comparative Example 8

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 13 except that the resin composition was changed asshown in Table 12. The solid amine was previously dissolved in theliquid amine, and then mixed with the epoxy resin. The evaluationresults are shown in Table 12. The glass transition temperature was 165°C. and the epoxy resin composition was satisfactory in heat resistance,but the rubbery state elastic modulus was as high as 15.0 MPa. As aresult, the tensile strength translation rate of the fiber reinforcedmaterial was 67%, and was insufficient.

Comparative Example 9

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 31 except that the resin composition was changed asshown in Table 12. The evaluation results are shown in Table 12. Theglass transition temperature was 134° C. and satisfactory, but therubbery state elastic modulus was as high as 12.1 MPa. As a result, thetensile strength translation rate of the fiber reinforced material was71%, and was insufficient.

Comparative Example 10

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 31 except that the resin composition was changed asshown in Table 12. The evaluation results are shown in Table 12. Therubbery state elastic modulus was 4.0 MPa and was satisfactory, but theglass transition temperature was 73° C. As a result, the fiberreinforced material had a glass transition temperature of 75° C., andwas insufficient in heat resistance.

Comparative Example 11

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 35 except that the resin composition was changed asshown in Table 13. The evaluation results are shown in Table 13. Theglass transition temperature was 116° C. and satisfactory, but therubbery state elastic modulus was as high as 12.4 MPa. As a result, thetensile strength translation rate of the fiber reinforced material was69%, and was insufficient.

Comparative Example 12

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 35 except that the resin composition was changed asshown in Table 13. The evaluation results are shown in Table 13. Theglass transition temperature was 136° C. and satisfactory, but therubbery state elastic modulus was as high as 11.8 MPa. As a result, thetensile strength translation rate of the fiber reinforced material was69%, and was insufficient.

Comparative Example 13

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 35 except that the resin composition was changed asshown in Table 13. The evaluation results are shown in Table 13. Theglass transition temperature was 125° C. and satisfactory, but therubbery state elastic modulus was as high as 11.0 MPa. As a result, thetensile strength translation rate of the fiber reinforced material was70%, and was insufficient.

Comparative Example 14

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 35 except that the resin composition was changed asshown in Table 13. The evaluation results are shown in Table 13. Therubbery state elastic modulus was 6.7 MPa and was satisfactory, but theglass transition temperature was 66° C. As a result, the fiberreinforced material had a glass transition temperature of 68° C., andwas insufficient in heat resistance.

Comparative Example 15

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 55 except that the resin composition was changed asshown in Table 13. The evaluation results are shown in Table 13. Therubbery state elastic modulus was 3.3 MPa and was satisfactory, but theglass transition temperature was 86° C. As a result, the fiberreinforced material had a glass transition temperature of 89° C., andwas insufficient in heat resistance.

Comparative Example 16

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 55 except that the resin composition was changed asshown in Table 13. The evaluation results are shown in Table 13. Theglass transition temperature was 145° C. and satisfactory, but therubbery state elastic modulus was as high as 13.2 MPa. As a result, thetensile strength translation rate of the fiber reinforced material was70%, and was insufficient.

Comparative Example 17

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 55 except that the resin composition was changed asshown in Table 13. The evaluation results are shown in Table 13. Therubbery state elastic modulus was 5.2 MPa and was satisfactory, but theglass transition temperature was 85° C. As a result, the fiberreinforced material had a glass transition temperature of 87° C., andwas insufficient in heat resistance.

Comparative Example 18

An epoxy resin composition and a cured resin were produced in the samemanner as in Example 55 except that the resin composition was changed asshown in Table 13. The evaluation results are shown in Table 13. Therubbery state elastic modulus was 6.4 MPa and was satisfactory, but theglass transition temperature was 70° C. As a result, the fiberreinforced material had a glass transition temperature of 72° C., andwas insufficient in heat resistance.

Comparative Example 19

An epoxy resin composition was produced according to the methoddescribed in Example 2 of Patent Document 1 (Published JapaneseTranslation No. 2015-508125). The obtained cured resin had a high glasstransition temperature of 170° C., but had a high rubbery state elasticmodulus of 16.9 MPa (Table 14). This epoxy resin composition had a highviscosity, and did not impregnate into the fiber by <Method forproducing fiber reinforced material>. As a result, a large amount ofvoids were produced in the fiber reinforced material. Therefore, theepoxy resin composition was heated to 70° C. for rapid impregnation togive an epoxy resin-impregnated carbon fiber sheet. Then, a fiberreinforced material was obtained in the same manner as in <Method forproducing fiber reinforced material>. The tensile strength translationrate of the obtained fiber reinforced material was 65%, and wasinsufficient.

Comparative Example 20

An epoxy resin composition was produced according to the methoddescribed in Example 9 of Patent Document 2 (Japanese Patent Laid-openPublication No. 2010-150311). The cured resin obtained by curing theepoxy resin composition had a satisfactory glass transition temperatureof 180° C., but had a high rubbery state elastic modulus of 14.2 MPa(Table 14). As a result, the tensile strength translation rate of thefiber reinforced material was 69%, and was insufficient.

Comparative Example 21

An epoxy resin composition was produced according to the methoddescribed in Example 15 of Patent Document 2 (Japanese Patent Laid-openPublication No. 2010-150311). The cured resin obtained by curing theepoxy resin composition had a high glass transition temperature of 185°C., but had a high rubbery state elastic modulus of 16.0 MPa (Table 14).As a result, the tensile strength translation rate of the fiberreinforced material was 65%, and was insufficient.

Comparative Example 22

Using the resin and the hardener described in Example 1 of PatentDocument 6 (Published Japanese Translation No. 2008-508113), an epoxyresin composition was produced according to <Method for preparing epoxyresin composition> since the patent document does not describe theconditions for preparing the epoxy resin composition. The cured resinobtained by curing the epoxy resin composition had a high glasstransition temperature of 182° C., but had a high rubbery state elasticmodulus of 19.2 MPa (Table 14). Since this epoxy resin composition had ahigh viscosity, an epoxy resin-impregnated carbon fiber sheet wasobtained in the same manner as in Comparative Example 5. Then, a fiberreinforced material was obtained in the same manner as in <Method forproducing fiber reinforced material>. The tensile strength translationrate of the obtained fiber reinforced material was 63%, and wasinsufficient.

Comparative Example 23

An epoxy resin composition was produced according to the methoddescribed in Example 6 of Patent Document 5 (Japanese Patent Laid-openPublication No. 2001-323046). The cured resin obtained by curing theepoxy resin composition had a high glass transition temperature of 173°C., but had a very high rubbery state elastic modulus of 18.0 MPa (Table14). This epoxy resin composition had a very high viscosity, and noepoxy resin-impregnated carbon fiber sheet was obtained by the methodshown in <Method for producing fiber reinforced material> or ComparativeExample 5. Accordingly, the epoxy resin composition was dissolved inacetone, and the resulting liquid resin was impregnated into a carbonfiber and then dried under reduced pressure to distill off acetone,whereby an epoxy resin-impregnated carbon fiber sheet was produced.Then, a fiber reinforced material was obtained in the same manner as in<Method for producing fiber reinforced material>. The tensile strengthtranslation rate of the obtained fiber reinforced material was 63%, andwas insufficient.

Comparative Example 24

An epoxy resin composition (base resin composition) was producedaccording to the method described in Example 3 of Patent Document 6(Published Japanese Translation No. 2008-508113). The cured resinobtained by curing the epoxy resin composition had a high glasstransition temperature of 140° C., but had a very high rubbery stateelastic modulus of 13.8 MPa (Table 14). A fiber reinforced material wasproduced from the obtained epoxy resin composition, and subjected to atensile test. As a result, the tensile strength translation rate was70%, and was insufficient.

Comparative Example 25

An epoxy resin composition was produced according to the methoddescribed in Example 4 of Patent Document 7 (Japanese Patent Laid-openPublication No. 2012-56980). The obtained cured resin had a satisfactoryglass transition temperature of 128° C., but had a high rubbery stateelastic modulus of 13.2 MPa. (Table 15) As a result, the tensilestrength translation rate of the fiber reinforced material was 70%, andwas insufficient.

Comparative Example 26

An epoxy resin composition was produced according to the methoddescribed in Example 7 of Patent Document 8 (Japanese Patent Laid-openPublication No. 2015-3938). The obtained cured resin had a high glasstransition temperature of 184° C., but had a very high rubbery stateelastic modulus of 18.8 MPa. (Table 15) As a result, the tensilestrength translation rate of the fiber reinforced material was 65%, andwas insufficient.

Comparative Example 27

An epoxy resin composition was produced according to the methoddescribed in Example 2 of Patent Document 9 (Japanese Patent Laid-openPublication No. 2013-1711). The obtained cured resin had a satisfactoryglass transition temperature of 121° C., but had a high rubbery stateelastic modulus of 13.0 MPa. (Table 15) As a result, the tensilestrength translation rate of the fiber reinforced material was 70%, andwas insufficient.

Comparative Example 28

An epoxy resin composition was produced according to the methoddescribed in Example 1 of Patent Document 10 (Japanese Patent Laid-openPublication No. 2005-120127). The obtained cured resin had a high glasstransition temperature of 203° C., but had a very high rubbery stateelastic modulus of 25.0 MPa (Table 15). This epoxy resin composition hada high viscosity, and did not impregnate into the fiber by <Method forproducing fiber reinforced material>. As a result, a large amount ofvoids were produced in the fiber reinforced material. Therefore, theepoxy resin composition was heated to 70° C. for impregnation to give anepoxy resin-impregnated carbon fiber sheet. Then, a fiber reinforcedmaterial was obtained in the same manner as in <Method for producingfiber reinforced material>. The tensile strength translation rate of theobtained fiber reinforced material was 61%, and was insufficient.

Comparative Example 29

An epoxy resin composition (base resin composition) was producedaccording to the method described in Example 14 of Patent Document 11(Japanese Patent Laid-open Publication No. 2010-59225). The cured resinobtained by curing the epoxy resin composition had a high glasstransition temperature of 193° C., but had a very high rubbery stateelastic modulus of 21.1 MPa (Table 15). This epoxy resin composition hada very high viscosity, and no epoxy resin-impregnated carbon fiber sheetwas obtained by the method shown in <Method for producing fiberreinforced material> or Comparative Example 28. Accordingly, the epoxyresin composition was dissolved in acetone, and the resulting liquidresin was impregnated into a carbon fiber and then dried under reducedpressure to distill off acetone, whereby an epoxy resin-impregnatedcarbon fiber sheet was produced. Then, a fiber reinforced material wasobtained in the same manner as in <Method for producing fiber reinforcedmaterial>. The tensile strength translation rate of the obtained fiberreinforced material was 61%, and was insufficient.

Comparative Example 30

An epoxy resin composition was produced according to the methoddescribed in Example 6 of Patent Document 4 (Japanese Patent No.4687167). The cured resin obtained by curing the epoxy resin compositionhad a glass transition temperature of 105° C., but had a high rubberystate elastic modulus of 11.2 MPa (Table 15). Since this epoxy resincomposition had a high viscosity, an epoxy resin-impregnated carbonfiber sheet was obtained in the same manner as in Comparative Example29. Then, a fiber reinforced material was obtained in the same manner asin <Method for producing fiber reinforced material>. The tensilestrength translation rate of the obtained fiber reinforced material was70%, and was insufficient.

Comparative Example 31

An epoxy resin composition was produced according to the methoddescribed in Example 18 of Patent Document 12 (Japanese Patent Laid-openPublication No. 2012-67190). The cured resin obtained by curing theepoxy resin composition had a glass transition temperature of 169° C.,but had a high rubbery state elastic modulus of 15.0 MPa (Table 16).Since this epoxy resin composition had a very high viscosity, an epoxyresin-impregnated carbon fiber sheet was obtained in the same manner asin Comparative Example 29. Then, a fiber reinforced material wasobtained in the same manner as in <Method for producing fiber reinforcedmaterial>. The tensile strength translation rate of the obtained fiberreinforced material was 67%, and was insufficient.

Comparative Example 32

An epoxy resin composition was produced according to the methoddescribed in Example 5 of Patent Document 13 (International PublicationNo. 2011/118106). The cured resin obtained by curing the epoxy resincomposition had a glass transition temperature of 162° C., but had ahigh rubbery state elastic modulus of 13.2 MPa (Table 16). Since thisepoxy resin composition had a very high viscosity, an epoxyresin-impregnated carbon fiber sheet was obtained in the same manner asin Comparative Example 29. Then, a fiber reinforced material wasobtained in the same manner as in <Method for producing fiber reinforcedmaterial>. The tensile strength translation rate of the obtained fiberreinforced material was 72%, and was insufficient.

Comparative Example 33

An epoxy resin composition was produced according to the methoddescribed in Example 2 of Patent Document 14 (Japanese Patent Laid-openPublication No. 63-86758). The cured resin obtained by curing the epoxyresin composition had a glass transition temperature of 205° C., but hada high rubbery state elastic modulus of 19.3 MPa (Table 16). Since thisepoxy resin composition had a very high viscosity, an epoxyresin-impregnated carbon fiber sheet was obtained in the same manner asin Comparative Example 29. Then, a fiber reinforced material wasobtained in the same manner as in <Method for producing fiber reinforcedmaterial>. The tensile strength translation rate of the obtained fiberreinforced material was 61%, and was insufficient.

TABLE 1 Example Example Example Example Example Example Constituentelement Component 1 2 3 4 5 6 [A] [a1] Tetraglycidyldiaminodiphenylmethane 25 10 25 25 25 25 (“SUMI-EPOXY (registeredtrademark)” ELM434) Triglycidyl-p-aminophenol (“Araldite (registeredtrademark)” MY0500) [a2] Diglycidyl orthotoluidine 30 (GOT) Diglycidylaniline 30 30 30 30 30 (GAN) Constituent element Fluorene epoxy resin 20[A] other than [a1] (“OGSOL (registered trademark)” PG-100) and [a2]Bis-A epoxy resin 45 60 45 45 45 (“jER (registered trademark)” 828)Bis-F epoxy resin 25 (“jER (registered trademark)” 830) Biphenyl epoxyresin (“jER (registered trademark)” YX4000) [B] [b1]Diethyltoluenediamine 19 18 18 (“Aradur (registered trademark)” 5200)3,3′-Dimethyl-4,4′-diaminodicyclohexylmethane 24 25 24 (“Baxxodur(registered trademark)” EC331) 2,6-Diaminotoluene [b2] Isophoronediamine10 9 12 9 (“Baxxodur (registered trademark)” EC201)4,4′-Methylenebiscyclohexylamine 13 1,3-Bisaminomethylcyclohexane 11N-Cyclohexyl-1,3-propanediamine Curing conditions Curing conditions A AA A A A Resin properties Viscosity (mPa · s) 1244 1203 1325 1305 13181337 Tg of cured product (° C.) 131 116 125 138 130 129 Rubbery stateelastic modulus (MPa) 8.2 8.3 7.5 8.9 8.0 8.5 CFRP properties Tg (° C.)132 117 125 137 131 130 Tensile strength translation rate (%) 78 77 7876 78 77

TABLE 2 Example Example Example Example Example Example Constituentelement Component 7 8 9 10 11 12 [A] [a1] Tetraglycidyldiaminodiphenylmethane 25 30 50 20 25 (“SUMI-EPOXY (registeredtrademark)” ELM434) Triglycidyl-p-aminophenol 20 (“Araldite (registeredtrademark)” MY0500) [a2] Diglycidyl orthotoluidine 30 30 (GOT)Diglycidyl aniline 30 10 30 30 (GAN) Constituent element Fluorene epoxyresin [A] other than [a1] (“OGSOL (registered trademark)” PG-100) and[a2] Bis-A epoxy resin 45 60 25 45 (“jER (registered trademark)” 828)Bis-F epoxy resin 20 25 (“jER (registered trademark)” 830) Biphenylepoxy resin 25 25 (“jER (registered trademark)” YX4000) [B] [b1]Diethyltoluenediamine 18 23 20 20 (“Aradur (registered trademark)” 5200)3,3′-Dimethyl-4,4′-diaminodicyclohexylmethane 26 (“Baxxodur (registeredtrademark)” EC331) 2,6-Diaminotoluene 17 [b2] Isophoronediamine 9 11(“Baxxodur (registered trademark)” EC201)4,4′-Methylenebiscyclohexylamine 8 1,3-BisaminomethylcyclohexaneN-cyclohexyl-1,3-propanediamine 12 11 10 Curing conditions Curingconditions A A A A A A Resin properties Viscosity (mPa · s) 1324 15771223 824 1203 1280 Tg of cured product (° C.) 126 135 140 122 124 128Rubbery state elastic modulus (MPa) 7.3 9.8 10.0 5.1 5.1 8.4 CFRPproperties Tg (° C.) 128 136 139 122 125 129 Tensile strengthtranslation rate (%) 79 76 75 81 81 78

TABLE 3 Example Example Example Example Example Constituent elementComponent 13 14 15 16 17 [A] [a1] Tetraglycidyl diaminodiphenylmethane60 60 (“Araldite (registered trademark)” MY721)Triglycidyl-p-aminophenol 60 70 (“jER (registered trademark)” 630)N,N,N′,N′-tetraglycidyl-m-xylenediamine 60 (“TETRAD (registeredtrademark)”-X) Constituent element Liquid bisphenol A epoxy resin 40 [A]other than [a1] (“jER (registered trademark)” 825) Liquid bisphenol Fepoxy resin 40 40 40 30 (“jER (registered trademark)” 806) Glycidylaniline (GAN) Glycidyl orthotoluidine (GOT) [B] [b1]Diethyltoluenediamine 25.8 36.1 24.6 (“Etacure (registered trademark)”100) 2,2′-Dimethyl-4,4′-methylenebiscyclohexylamine 24.0 28.5 (“Baxxodur(registered trademark)” EC331)4,4′-Diamino-3,3′,5,5′-tetraethyldiphenylmethane (“KAYABOND (registeredtrademark)” C-300S) [b3] 4-Aminodiphenyl ether 25.8 28.54-Aminodiphenylmethane 36.0 36.9 2-Aminodiphenylsulfone 15.5 Curingconditions Curing conditions A A A A A Resin properties Tg of curedproduct (° C.) 139 131 146 132 128 Rubbery state elastic modulus (MPa)6.8 7.8 9.8 6.3 5.2 CFRP properties Tg (° C.) 140 133 146 134 129Tensile strength translation rate (%) 80 78 75 81 82

TABLE 4 Example Example Example Example Example Constituent elementComponent 18 19 20 21 22 [A] [a1] Tetraglycidyl diaminodiphenylmethane35 60 70 (“Araldite (registered trademark)” MY721)Triglycidyl-p-aminophenol (“jER (registered trademark)” 630)N,N,N′,N′-tetraglycidyl-m-xylenediamine 70 35 60 (“TETRAD (registeredtrademark)”-X) Constituent element Liquid bisphenol A epoxy resin 10 [A]other than [a1] (“jER (registered trademark)” 825) Liquid bisphenol Fepoxy resin 30 30 20 (“jER (registered trademark)” 806) Glycidyl aniline20 30 (GAN) Glycidyl orthotoluidine 30 (GOT) [B] [b1]Diethyltoluenediamine 18.0 40.0 (“Etacure (registered trademark)” 100)2,2′-Dimethyl-4,4′-methylenebiscyclohexylamine 42.7 38.5 (“Baxxodur(registered trademark)” EC331)4,4′-Diamino-3,3′,5,5′-tetraethyldiphenylmethane 32.8 (“KAYABOND(registered trademark)” C-300S) [b3] 4-Aminodiphenyl ether 18.0 16.54-Aminodiphenylmethane 24.0 32.8 2-Aminodiphenylsulfone 18.3 10.0 Curingconditions Curing conditions A A A A A Resin properties Tg of curedproduct (°C.) 130 126 133 120 134 Rubbery state elastic modulus (MPa)5.9 3.8 4.0 4.5 8.3 CFRP properties Tg (° C.) 131 127 134 122 134Tensile strength translation rate (%) 81 84 84 83 77

TABLE 5 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Constituentelement Component ple 23 ple 24 ple 25 ple 26 ple 27 ple 28 ple 29 ple30 [A] [a1] Tetraglycidyl diaminodiphenylmethane 80 80 70 60 60(“Araldite (registered trademark)” MY721) Triglycidyl-p-aminophenol 60(“jER (registered trademark)” 630)N,N,N′,N′-tetraglycidyl-m-xylenediamine 80 80 (“TETRAD (registeredtrademark)”-X) Constituent Liquid bisphenol A epoxy resin 20 20 20 10 2020 element (“jER (registered trademark)” 825) [A] other Liquid bisphenolF epoxy resin 20 than [a1] (“jER (registered trademark)” 806) Glycidylaniline 30 30 20 20 (GAN) [B] [b1] Diethyltoluenediamine 21.0 14.3 12.8(“Etacure (registered trademark)” 100)2,2′-Dimethyl-4,4′-methylenebiscyclohexylamine 14.4 36.1 17.0 29.4(“Baxxodur (registered trademark)” EC331)4,4′-Diamino-3,3′,5,5′-tetraethyldiphenylmethane 19.2 35.7 (“KAYABOND(registered trademark)” C-300S) [b3] p-Toluidine 21.0 15.33-Methylaniline 28.8 15.5 3-Ethylaniline 33.7 12.8 3-Isopropylaniline33.3 19.6 Curing conditions Curing conditions A A A A A A A A Resinproperties Tg of cured product (° C.) 123 113 124 116 124 125 128 112Rubbery state elastic modulus (MPa) 6.6 5.7 5.0 4.1 6.9 5.3 5.5 3.6 CFRPproperties Tg (° C.) 124 115 125 117 126 125 129 115 Tensile strengthtranslation rate (%) 80 81 83 83 79 82 82 84

TABLE 6 Example Example Example Example Constituent element Component 3132 33 34 [A] [a3] Fluorene epoxy resin 30 25 (“OGSOL (registeredtrademark)” PG-100) Fluorene epoxy resin 30 25 (“OGSOL (registeredtrademark)” EG-200) Constituent element Liquid bisphenol A epoxy resin70 70 50 [A] other than [a3] (“jER (registered trademark)” 828) Liquidbisphenol F epoxy resin 50 (“jER (registered trademark)” 830) Diglycidylaniline 25 (GAN) Tetraglycidyl diaminodiphenylmethane 25 (“SUMI-EPOXY(registered trademark)” ELM434) [B] [b4] 3-Dodecenyl succinic anhydride28 57 42 59 (“RIKACID (registered trademark)” DDSA) [b5] Methyltetrahydrophthalic anhydride 57 62 (HN-2200) Methyl nadic anhydride 4359 (“KAYAHARD (registered trademark)” MCD) Accelerator DBU-octylate 2 22 2 (“U-CAT (registered trademark)” SA102) Curing conditions Curingconditions A A A A Resin properties Viscosity (mPa · s) 1224 1810 7511120 Glass transition temperature (° C.) 120 125 116 135 Rubbery stateelastic modulus (MPa) 4.6 5.1 4.0 6.3 CFRP properties Tg (° C.) 121 126117 137 Tensile strength translation rate (%) 82 82 82 80

TABLE 7 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Constituent elementComponent ple 35 ple 36 ple 37 ple 38 ple 39 ple 40 ple 41 [A] [a2]Diglycidyl aniline 50 60 60 50 50 25 (GAN) Diglycidyl orthotoluidine 25(GOT) [a4] Tetraglycidyl diaminodiphenylmethane 15 (“SUMI-EPOXY(registered trademark)” ELM434) Constituent element Fluorene epoxy resin25 25 [A] other than [a2] (“OGSOL (registered trademark)” PG-100) and[a4] Bis-A epoxy resin 35 50 25 (“jER (registered trademark)” 828) Bis-Fepoxy resin (“jER (registered trademark)” 830) [C] p-tert-Butyl phenylglycidyl ether 15 40 25 40 35 25 25 (“Denacol (registered trademark)”EX-146) [B] Methyl tetrahydrophthalic anhydride 119 100 90 90 90 83(HN-2200) Methyl nadic anhydride 106 (“KAYAHARD (registered trademark)”MCD) Accelerator DBU salt 2 2 2 2 2 2 2 (“U-CAT (registered trademark)”SA102) Curing conditions Curing conditions A A A A A A A Resinproperties Viscosity (mPa · s) 374 64 558 206 190 452 723 Tg of curedproduct (° C.) 130 104 112 111 126 116 132 Rubbery state elastic modulus(MPa) 10.0 4.6 5.7 4.7 5.5 4.3 6.0 CFRP properties Tg (° C.) 132 106 114113 127 118 133 Tensile strength translation rate (%) 74 82 81 80 81 8280

TABLE 8 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Constituent elementComponent ple 42 ple 43 ple 44 ple 45 ple 46 ple 47 ple 48 [A] [a2]Diglycidyl aniline 30 30 25 (GAN) Diglycidyl orthotoluidine 35 35 (GOT)[a4] Tetraglycidyl diaminodiphenylmethane 45 10 10 (“SUMI-EPOXY(registered trademark)” ELM434) Constituent element Fluorene epoxy resin30 [A] other than [a2] (“OGSOL (registered trademark)” PG-100) and [a4]Bis-A epoxy resin 40 30 55 (“jER (registered trademark)” 828) Bis-Fepoxy resin 35 35 (“jER (registered trademark)” 830) [C] p-tert-Butylphenyl glycidyl ether 55 40 30 35 (“Denacol (registered trademark)”EX-146) o-Phenyl phenyl glycidyl ether 30 30 (“Denacol (registeredtrademark)” EX-142) Epoxy resin other than Phenyl glycidyl ether 35constituent elements [A] (“Denacol (registered trademark)” EX-141) and[C] [B] Methyl tetrahydrophthalic anhydride 93 94 (HN-2200) Methyl nadicanhydride 103 89 96 99 101 (“KAYAHARD (registered trademark)” MCD)Accelerator DBU salt 3 2 (“U-CAT (registered trademark)” SA102)N,N-Dimethylbenzylamine 4 3 4 4 (“KAOLIZER (registered trademark)” No.20) 2-Ethyl-4-methylimidaxole 1 (“Curezol (registered trademark)” 2E4MZ)Curing conditions Curing conditions A A A A A A A Resin propertiesViscosity (mPa · s) 642 872 235 252 318 562 687 Tg of cured product(°C.) 97 125 115 109 124 128 97 Rubbery state elastic modulus (MPa) 6.55.2 4.2 4.7 4.8 5.2 10.0 CFRP properties Tg (° C.) 98 127 116 109 127129 98 Tensile strength translation rate (%) 80 81 82 80 80 81 75

TABLE 9 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Constituent elementComponent ple 49 ple 50 ple 51 ple 52 ple 53 ple 54 ple 55 [A] [a2]Diglycidyl aniline 25 30 25 30 (GAN) [a4] Tetraglycidyldiaminodiphenylmethane 40 30 45 30 (“SUMI-EPOXY (registered trademark)”ELM434) Constituent Fluorene epoxy resin 30 element [A] (“OGSOL(registered trademark)” PG-100) other than [a2] Bis-A epoxy resin 50 5040 and [a4] (“jER (registered trademark)” 828) Bis-F epoxy resin 100(“jER (registered trademark)” 830) Triglycidyl-p-aminophenol (“Araldite(registered trademark)” MY0500) [C] p-tert-Butyl phenyl glycidyl ether25 30 25 30 25 40 (“Denacol (registered trademark)” EX-146) [B]Diethyltoluenadiamine 25 29 26 32 22 (“Aradur (registered trademark)”5200) Poly(propylene glycol) diamine 20.7 (“JEFFAMINE (registeredtrademark)” D230) Poly(propylene glycol) diamine 10 10 13 (“JEFFAMINE(registered trademark)” D400) Isophoronediamine 8.9 (“Baxxodur(registered trademark)” EC201)3,3′-Dimethyl-4,4′-diaminodicyclohexylmethane 34 (“Baxxodur (registeredtrademark)” EC331) Curing conditions Curing conditions A A B A A A AResin properties Viscosity (mPa · s) 872 857 1027 1187 872 1265 562 Tgof cured product (° C.) 110 122 97 113 120 106 97 Rubbery state elasticmodulus (MPa) 4.6 5.1 3.1 5.3 4.5 3.4 9.9 CFRP properties Tg (° C.) 111124 98 115 123 107 98 Tensile strength translation rate (%) 82 82 83 8182 82 75

TABLE 10 Example Example Example Example Example Example Constituentelement Component 56 57 58 59 60 61 [A] [a2] Diglycidyl aniline 25 25 5025 35 40 (GAN) [a4] Tetraglycidyl diaminodiphenylmethane 10 (“SUMI-EPOXY(registered trademark)” ELM434) Constituent Fluorene epoxy resin 5element [A] (“OGSOL (registered trademark)” PG-100) other than [a2]Bis-A epoxy resin 50 50 35 15 30 15 and [a4] (“jER (registeredtrademark)” 828) Triglycidyl-p-aminophenol (“Araldite (registeredtrademark)” MY0500) [C] p-tert-Butyl phenyl glycidyl ether 25 25 15 6030 25 (“Denacol (registered trademark)” EX-146) [B]Diethyltoluenediamine 16 25 (“Aradur (registered trademark)” 5200)Isophoronediamine 8 12 20.1 15.1 (“Baxxodur (registered trademark)”EC201) 3,3′-Dimethyl-4,4′-diaminodicyclohexylmethane 18 40 8.6 15.1(“Baxxodur (registered trademark)” EC331) Curing conditions Curingconditions A B B A B B Resin properties Viscosity (mPa · s) 865 950 587568 859 786 Tg of cured product (° C.) 101 108 131 96 117 120 Rubberystate elastic modulus (MPa) 4.7 3.0 9.8 5.5 4.3 4.4 CFRP properties Tg(° C.) 104 107 134 98 118 122 Tensile strength translation rate (%) 8184 75 80 83 83

TABLE 11 Constituent Comparative Comparative Comparative Comparativeelement Component Example 1 Example 2 Example 3 Example 4 [A] [a1]Tetraglycidyl diaminodiphenylmethane 55 25 25 (“SUMI-EPOXY (registeredtrademark)” ELM434) [a2] Diglycidyl aniline 55 30 30 (GAN) Constituentelement [A] Bis-A epoxy resin 45 45 45 45 other than [a1] and [a2] (“JER(registered trademark)” 828) [B] [b1] Diethyltoluenediamine 19 20 30(“Aradur (registered trademark)” 5200) [b2] Isophoronediamine 10 10 28(“Baxxodur (registered trademark)” EC201) Curing conditions Curingconditions A A A A Resin properties Viscosity (mPa · s) 784 1785 12251252 Tg of cured product (° C.) 115 146 133 131 Rubbery state elasticmodulus (MPa) 11.0 15.2 14.1 12.9 CFRP properties Tg (° C.) 116 148 136133 Tensile strength translation rate (4) 72 68 68 71

TABLE 12 Compar- Compar- Compar- Compar- Compar- Compar- ative ativeative ative ative ative Constituent element Component Example 5 Example6 Example 7 Example 8 Example 9 Example 10 [A] Tetraglycidyldiaminodiphenylmethane 60 19 (“Araldite (registered trademark)” MY721)Triglycidyl-p-aminephenol 60 10 (“jER (registered trademark)” 630) Bis-Aepoxy resin 100 100 (“jER (registered trademark)” 828) Liquid bisphenolA epoxy resin 100 40 (“jER (registered trademark)” 825) Liquid bisphenolF epoxy resin 40 35 (“jER (registered trademark)” 806) Glycidyl aniline15 (GAN) [B] 3,3′-Dimethyl-4,4′-diaminodicyclohexylmethane 18.1 51.3(“Baxxodur (registered trademark)” EC331) Diethyltoluenediamine 27.1(“jER Cure (registered trademark)” W) 4-Aminodiphenylmethane 27.1 71.13,3′-Diaminodiphenylsulfone 7.7 (3,3′-DAS) 4,4′-Diaminodiphenylaulfone3.9 (“SEIKACURE (registered trademark)” S) 3-Dodecenyl succinicanhydride 134 (“RIKACID (registered trademark)” DDSA) Methyltetrahydrophthalic anhydride 83 (HN-2200) Accelerator DBU-octylate 2 2(“U-CAT (registered trademark)” SA102) Other ingredients Core-shellrubber-containing tetraglycidyl 28.0 diaminodiphenylmethane (“Kane Ace(registered trademark)” MX-416) 4-t-Butylcatechol 1.0 (DIC-TBC) Curingconditions Curing conditions A A A A A A Resin properties Tg of curedproduct (° C.) 92 90 157 165 134 73 Rubbery state elastic modulus (MPa)9.5 7.8 13.0 15.0 12.1 4.0 CFRP properties Tg (° C.) 94 93 158 166 13675 Tensile strength translation rate (%) 76 78 71 67 71 82

TABLE 13 Compar- Compar- Compar- Compar- Compar- ative Ex- ative Ex-ative Ex- ative Ex- ative Ex- Constituent element Component ample 11ample 12 ample 13 ample 14 ample 15 [A] Diglycidyl aniline 25 50 25(GAN) Tetraglycidyl diaminodiphenylmethane (“SUMI-EPOXY (registeredtrademark)” ELM434) Fluorene epoxy resin 25 25 (“OGSOL (registeredtrademark)” PG-100) Bis-A epoxy resin 25 25 75 50 50 (“jER (registeredtrademark)” 828) [C] p-tert-Butyl phenyl glycidyl ether 25 (“Denacol(registered trademark)” EX-146) Epoxy resin other than Phenyl glycidylether 25 50 25 [A] and [C] (“Denacol (registered trademark)” EX-141) [B]Methyl tetrahydrophthalic anhydride 91 95 84 98 (HN-2200)Diethyltoluenediamine (“Aradur (registered trademark)” 5200)Isophoronediamine 14 (“Baxxodur (registered trademark)” EC201)3,3′-Dimethyl-4,4′-diaminodicyclohexylmethane 19 (“Baxxodur (registeredtrademark)” EC331) Accelerator DBU salt 2 2 2 2 (“U-CAT (registeredtrademark)” SA102) Curing conditions Curing conditions A A A A B Resinproperties Tg of cured product (° C.) 116 136 125 66 86 Rubbery stateelastic modulus (MPa) 12.4 11.8 11.0 6.7 3.3 CFRP properties Tg (° C.)118 138 126 68 89 Tensile strength translation rate (%) 69 69 70 79 82Compar- Compar- Compar- ative Ex- ative Ex- ative Ex- Constituentelement Component ample 16 ample 17 ample 18 [A] Diglycidyl aniline 50(GAN) Tetraglycidyl diaminodiphenylmethane 30 (“SUMI-EPOXY (registeredtrademark)” ELM434) Fluorene epoxy resin (“OGSOL (registered trademark)”PG-100) Bis-A epoxy resin 20 60 80 (“jER (registered trademark)” 828)[C] p-tert-Butyl phenyl glycidyl ether 40 (“Denacol (registeredtrademark)” EX-146) Epoxy resin other than Phenyl glycidyl ether 50 (A)and [C] (“Denacol (registered trademark)” EX-141) [B] Methyltetrahydrophthalic anhydride (HN-2200) Diethyltoluenediamine 27 (“Aradur(registered trademark)” 5200) Isophoronediamine (“Baxxodur (registeredtrademark)” EC201) 3,3′-Dimethyl-4,4′-diaminodicyclohexylmethane 46 30(“Baxxodur (registered trademark)” EC331) Accelerator DBU salt (“U-CAT(registered trademark)” SA102) Curing conditions Curing conditions B B AResin properties Tg of cured product (° C.) 145 85 70 Rubbery stateelastic modulus (MPa) 13.2 5.2 6.4 CFRP properties Tg (° C.) 148 87 72Tensile strength translation rate (%) 70 82 80

TABLE 14 Comparative Comparative Comparative Comparative ComparativeComparative Example 19 Example 20 Example 21 Example 22 Example 23Example 24 Resin Tg of cured product (° C.) 170 180 185 182 173 140properties Rubbery state elastic modulus (MPa) 16.9 14.2 16.0 19.2 18.013.8 CFRP Tg (° C.) 172 183 189 185 175 142 properties Tensile strengthtranslation rate (%) 65 69 65 63 63 70

TABLE 15 Comparative Comparative Comparative Comparative ComparativeComparative Component Example 25 Example 26 Example 27 Example 28Example 29 Example 30 Resin Tg of cured product (° C.) 128 184 121 203193 105 properties Rubbery state elastic modulus (MPa) 13.2 18.8 13.025.0 21.1 11.2 CFRP Tg (° C.) 129 187 122 205 195 108 properties Tensilestrength translation rate (%) 70 65 70 61 61 70

TABLE 16 Compar- Compar- Compar- ative Ex- ative Ex- ative Ex- Componentample 31 ample 32 ample 33 Resin Tg of cured product (° C.) 169 162 205prop- Rubbery state elastic 15.0 13.2 19.3 erties modulus (MPa) CFRP Tg(° C.) 171 163 204 prop- Tensile strength translation 67 72 61 ertiesrate (%)

The epoxy resin composition of the present invention is suitably usedfor producing a fiber reinforced material that combines heat resistancewith tensile strength translation rate at a high level. Further, theepoxy resin composition and the fiber reinforced material of the presentinvention are preferably used for sports applications, generalindustrial applications, and aerospace applications.

What is claimed:
 1. An epoxy resin composition comprising the followingconstituent elements [A] and [B], comprising the following constituentelements [a1] and [a2] as the constituent element [A], and comprisingthe following constituent elements [b1] and [b2] as the constituentelement [B], wherein the epoxy resin composition when cured into a curedproduct has a rubbery state elastic modulus in a dynamic viscoelasticityevaluation of 10 MPa or less, and the cured product has a glasstransition temperature of 95° C., or higher: [A] a bifunctional orhigher functional epoxy resin containing an aromatic ring; [B] an aminehardener; [a1] a trifunctional or higher functional aromatic epoxyresin; [a2] an optionally substituted diglycidyl aniline, wherein if thediglycidyl aniline is substituted the diglycidyl aniline bears at leastone substituent selected from the group consisting of an alkyl grouphaving 1 to 4 carbon atoms, a phenyl group, and a phenoxy group; [b1] acycloalkyldiamine having a substituent on a carbon atom adjacent to acarbon atom bonded to each amino group; and [b2] at least one amineselected from the group consisting of 4,4′-methylenebiscyclohexylamine,1,3-bisaminomethylcyclohexane, N-cyclohexyl-1,3-propanediamine, andisophoronediamine.
 2. The epoxy resin composition according to claim 1,comprising 20 to 40 parts by mass of the constituent element [a1] and 20to 60 parts by mass of the constituent element [a2] in 100 parts by massof the total epoxy resin.
 3. The epoxy resin composition according toclaim 1, having a viscosity at 25° C. of 2,000 mPa·s or less.
 4. A fiberreinforced material comprising a cured product of the epoxy resincomposition according to claim 1 and a reinforcing fiber.
 5. A moldedarticle comprising the fiber reinforced material according to claim 4.6. A pressure vessel comprising the fiber reinforced material accordingto claim
 4. 7. An epoxy resin composition, comprising the followingconstituent elements [A], [B] and [C], comprising the followingconstituent elements [a2] and [a4] as the constituent element [A], andcomprising the following constituent element [b1] as the constituentelement [B], wherein the epoxy resin composition when cured into a curedproduct has a rubbery state elastic modulus in a dynamic viscoelasticityevaluation of 10 MPa or less, and the cured product has a glasstransition temperature of 95° C., or higher: [A] a bifunctional orhigher functional epoxy resin containing an aromatic ring; [B] an aminehardener; [C] a monofunctional epoxy resin which is a phenyl glycidylether substituted with a tert-butyl group, a sec-butyl group, anisopropyl group, or a phenyl group; [a2] an optionally substituteddiglycidyl aniline, wherein if the diglycidyl aniline is substituted thediglycidyl aniline bears at least one substituent selected from thegroup consisting of an alkyl group having 1 to 4 carbon atoms, a phenylgroup, and a phenoxy group; [a4] tetraglycidyl diaminodiphenylmethane;and [b1] a cycloalkyldiamine having a substituent on a carbon atomadjacent to a carbon atom having an amino group.
 8. The epoxy resincomposition according to claim 7, comprising 20 to 50 parts by mass ofthe constituent element [C] in 100 parts by mass of the total epoxyresin.
 9. The epoxy resin composition according to claim 7, comprisingconstituent element [b1] and further comprising an aliphatic polyaminehaving an alkylene glycol structure as the constituent element [B]. 10.The epoxy resin composition according to claim 7, comprising constituentelement [b1] and further comprising isophoronediamine as the constituentelement [B].
 11. The epoxy resin composition according to claim 7,having a viscosity at 25° C. of 2,000 mPa·s or less.
 12. A fiberreinforced material comprising a cured product of the epoxy resincomposition according to claim 7 and a reinforcing fiber.
 13. A moldedarticle comprising the fiber reinforced material according to claim 12.14. A pressure vessel comprising the fiber reinforced material accordingto claim 12.